JP4364365B2 - Method and apparatus for controlling vehicle with electric assist function - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control method and apparatus applied to a vehicle with an electrically assisted function that controls an electric driving force relative to a human driving force based on an auxiliary rate characteristic stored in advance.
[0002]
[Prior art]
In a bicycle with an electric assist function that detects the pedaling force (human driving force) and controls the driving force (electric power driving force) of the electric motor according to the magnitude of the pedaling force, the output ratio of the electric motor to the pedaling force (assist rate, assist) The control method (assist ratio gradual reduction processing method in the high vehicle speed region) is known (Japanese Patent No. 2623419) in which the electric motor is driven and controlled by gradually decreasing the ratio in the high vehicle speed region with respect to the increase in vehicle speed.
[0003]
This method gives a limit by gradually decreasing the assist ratio with respect to the increase in vehicle speed in order to prevent unnecessary motor driving force from being applied at high speed and to prevent excessive vehicle speed as a bicycle. It is. In other words, an assist ratio characteristic (assist ratio characteristic) that keeps the assist ratio constant below the set vehicle speed and decreases the assist ratio above this set vehicle speed is stored in advance, and the motor driving force is calculated for each calculation processing cycle of the microcomputer. Meanwhile, the motor driving force is controlled. In addition, by gradually decreasing the assist ratio in the high vehicle speed range as described above, there is an effect of preventing wasteful consumption of the battery.
[0004]
The structure of the drive system of this bicycle with an electric assist function is a system in which two systems, a human power drive system and a motor drive system, are provided in parallel. A one-way clutch is interposed in the motor drive system and the motor is not energized. Or it has the structure which prevents that a motor is rotated when the vehicle speed by manual driving | running | working is faster than the rotational speed of a motor. Further, when transmitting the driving force of the motor driving system, the clutch is connected to transmit the driving force.
[0005]
The driving force (stepping force) of the human-powered driving system changes with a half rotation period of the crankshaft because it is input from the crank pedal. This is because the pedaling force becomes almost zero when the crank pedal comes to the top dead center or the bottom dead center. Since the motor is controlled so that its rotational speed becomes almost zero each time the pedal force becomes almost zero, that is, the motor driving force becomes zero, the motor driving force is almost zero. It fluctuates periodically with a desired driving force corresponding to the pedaling force obtained when the pedal is depressed.
[0006]
At this time, the motor has a state in which the one-way clutch is disengaged from a state where the speed is substantially zero to a rotational speed corresponding to the vehicle speed. When the one-way clutch is disengaged, the driving force of the motor does not contribute to traveling, and therefore, the driving force of the motor is delayed with respect to the pedaling force for the time required for acceleration of the motor. Due to this delay, the energy required to accelerate the motor is wasted. Also, because of this delay, the clutch is engaged when the motor actually starts to rotate, so that the shock is transmitted to the vehicle body, making the ride uncomfortable.
[0007]
In order to solve this problem, in Japanese Patent No. 2634121, when the vehicle speed is not zero and the manpower driving force (stepping force) is almost zero, the motor is driven and controlled at the rotational speed necessary to generate the vehicle speed at that time. The method is taken. According to this method, since the motor is driven so that the rotational speed of the motor substantially coincides with the vehicle speed at which the one-way clutch starts to be connected, the shock generated when the motor starts to rotate and the clutch is connected can be reduced. In addition, it is possible to prevent wasteful consumption of energy required for accelerating the motor.
[0008]
[Problems to be solved by the invention]
However, such a method is effective when the pedal force is continuously generated. However, for example, even when the vehicle speed is not zero but there is no pedal input and the vehicle is traveling in inertia, the voltage is always applied to the motor. As a result, the battery is wasted.
[0009]
In order to realize such a method, it is necessary to detect the actual vehicle speed when the motor driving force is substantially zero. For example, a rotation speed sensor for detecting the rotation speed of a crank or a wheel is required. In electric vehicles such as bicycles with battery-assisted functions that require cost reduction as described above, when the motor is rotating using the rotor position detection sensor used to control the motor By calculating the vehicle speed from the rotation speed of the rotor, it is possible to eliminate the vehicle speed sensor and reduce the cost.
[0010]
However, in such a system, the vehicle speed cannot be obtained when the motor is stopped, and the actual vehicle speed cannot be detected when the clutch is disengaged. Accordingly, there has been a problem in that the current corresponding to the vehicle speed cannot be supplied to the motor after the pedaling force performed in the above patent is lost.
[0011]
OBJECT OF THE INVENTION
The present invention has been made in view of such circumstances, and the driving force of the motor is driven by the one-way clutch being released until the motor speed reaches a rotational speed corresponding to the vehicle speed from a substantially zero state. Since it does not contribute, the motor driving force is delayed relative to the pedaling force by the time required for motor acceleration, thereby preventing the energy required for motor acceleration from being wasted, and the vehicle speed is not zero but there is no pedal input. When the vehicle is running inertially, the battery is not wasted, the vehicle has an electric assist function that does not have a sensor to detect the actual vehicle speed and calculates the vehicle speed from the rotational speed of the motor. The first object is to provide a method for controlling a vehicle with an electric assist function that does not cause any inconvenience. It is a second object of the present invention to provide a control device for a vehicle with an electrically assisted function that is directly used for carrying out this method.
[0012]
[Structure of the invention]
According to the present invention, a first object is to provide a human power driving system and an electric driving system in parallel, and to change the ratio of the electric power driving force (T _M ) to the human driving force (T _P ) together with the vehicle speed (V _SP ). In a control method of a vehicle with an electric auxiliary function that generates electric power driving force (T _M ) according to human power driving force (T _P ) based on a predetermined auxiliary rate characteristic, the power source of the electric driving system is configured by an electric motor When the human driving force (T _P ) is equal to or lower than the lower limit value (T _PL ), a follow-up current (i _ID ) that keeps the motor rotation speed (v) corresponding to the vehicle speed (V _SP ) at that time is supplied. and, while the human power (T _P) is kept the lower limit value (T _PL) the following conditions, the motor rotational speed (v) is a lower limit value (v _L) Examples assist stop condition that falls below electric auxiliary function with the vehicle, characterized in that interrupting the take Mawari current (i _ID) The method is accomplished by.
Further, when the assist stop condition is satisfied, the follow-up current (i _ID ) is cut off. Therefore, if the motor rotation speed (v) is reduced to the lower limit value (v _L ), the follow-up current (i _ID ) is not waited for a certain time. It is what cuts. For this reason, useless consumption of energy can be prevented.
[0013]
Here, the motor is a DC non-commutator motor (brushless DC motor), and the motor rotational speed (v) and the vehicle speed (V _SP ) are obtained using signals indicating the rotational position of the rotor detected by the rotational position detector of the motor. be able to. In this case, the vehicle speed (V _SP ) can be obtained by adding the reduction ratio of the electric drive system to the motor rotation speed (v).
[0014]
The assist stop condition is, for example, that the motor rotational speed (v) becomes lower than the lower limit value (v _L ) after the human power driving force (stepping force T _P ) is lower than the lower limit value (T _PL ) for a certain period of time. It can be. That can is continued over a certain time in this state (T _P ≦ T _PL), and further v blocked ≦ v _L and turned When turns with stops the assist current (i _ID), to prevent wasteful consumption of energy is there.
[0016]
The conditions for restarting the assist from the state in which the accompanying current (i _ID ) is supplied can be v> v _L and T _P ≧ T _PLR (assist restart lower limit). When the assist is resumed (at the time of re-acceleration assist), the assist rate (η _A ) is initially set smaller than the assist rate (η) obtained from the assist rate characteristic, and gradually increased with the passage of time. It is preferable to change so as to match the auxiliary rate (η) obtained from (1). By doing so, it is possible to reduce the shock at the time of restarting the assist and further improve the riding comfort.
[0017]
The second object is to provide a predetermined auxiliary rate characteristic in which a human power driving system and an electric driving system are provided in parallel, and the ratio of the electric power driving force (T _M ) to the human driving force (T _P ) is changed together with the vehicle speed (V _SP ). In the control device for a vehicle with an electrically assisted function that generates an electric power driving force (T _M ) according to the human power driving force (T _P ) based on the electric motor, an electric motor serving as a power source of the electric driving system, and a human power driving force (T _P ) and a follow-up current setting unit that obtains a follow-up current (i _ID ) based on the rotation speed (v) of the motor, and a state where the manpower driving force (T _P ) is below the lower limit (T _PL ) An assist stop condition discriminating unit for discriminating the assist stop condition based on the fact that the rotation speed (v) of the motor is lower than the lower limit value (v _L ) while maintaining the assist stop condition. Part determines that the assist stop condition is met Controller for the electric auxiliary function with the vehicle, characterized in that blocking the Child around current setting unit turns with current (i _ID), it is accomplished by.
[0018]
The electric motor may be a vector controlled direct current commutator motor (brushless DC motor). In this case, a target torque calculation unit for obtaining a target torque (T _M = T _P × η) of the motor corresponding to the vehicle speed (V _SP ) and the manpower driving force (stepping force T _P ) based on the auxiliary rate characteristic, and the target A torque current calculation unit for obtaining a motor current command value (i ₀ ^* ) corresponding to the torque (T _M ) by vector control, and a sum of i ₀ ^* and i _ID (i ₀ ^* + i _ID = i ^* ) are obtained. And an adder. The motor current is controlled based on this sum i ^* . For example, PWM (Pusle Width Modulation) control is performed.
[0019]
In this case, a speed current (i _SP ) may be added to the current command value i ^* . That is, a speed current calculation unit for _obtaining a motor current (speed current i _SP ) necessary for generating a motor rotation speed (v) corresponding to the vehicle speed (V _SP ), and this speed current (i _SP ) as a current command value i. ^What is necessary is just to add the adder which makes final electric current command value i ^* in addition to ^* . In this way, smoother motor speed control becomes possible.
[0020]
Embodiment
1 is a diagram showing a power transmission system when the present invention is applied to a battery-assisted bicycle, FIG. 2 is an explanatory diagram of a motor control device, FIG. 3 is a diagram explaining a configuration of an inverter, and FIG. 4 is a configuration of the control device. 5 is a conceptual diagram of the operation, FIG. 6 is an operation flowchart of the main flow, and FIG. 7 is an operation flowchart at the time of assist stop and assist restart according to the present invention.
[0021]
In FIG. 1, a driver's pedaling force is transmitted to a resultant force shaft 3 via a crankshaft 1 and a one-way clutch 2 driven by a pedal (not shown). Further, the output of the three-phase DC non-commutator motor 4 is transmitted to the resultant force shaft 3 via the speed reduction unit 5 and the one-way clutch 6. The rotation of the resultant force shaft 3 is transmitted to the rear wheel 8 which is a driving wheel via a free wheel clutch 7.
[0022]
The human power drive system is a transmission system from the crankshaft 1 to the rear wheel 8, and the electric drive system is a transmission system from the motor 4 to the rear wheel 8. Driving force or pedaling force T _P of human-driven system is detected by the depression force sensor 9 between the one-way clutch 2 and the resultant force shaft 3.
[0023]
Reference numeral 10 denotes a control device for the motor 4. The control device 10 controls the output torque T _M of the motor 4, that is, the motor current, based on the pedaling force T _P detected by the pedaling force sensor 9 and the vehicle speed V _SP detected by the vehicle speed sensor 11. Reference numeral 12 denotes a DC power source such as a battery. Here, the vehicle speed sensor 11 can be formed by a sensor (not shown) for detecting the rotational speed of the rear wheel 8, the front wheel (not shown), the rotating part of the drive system, or the like. The vehicle speed sensor 11 is configured by a circuit that detects a rotational speed by a counter electromotive voltage induced in an armature coil of the motor 4 or is calculated using a rotational speed v and a reduction ratio detected by an estimation unit 17 described later. It can also be configured with what is required.
[0024]
As shown in FIGS. 2 and 4, the control device 10 includes an inverter unit 13, a gate driving unit 14, and an arithmetic processing unit 15. As shown in FIG. 3, the inverter unit 13 is formed of a known three-phase bridge circuit. That is, two sets of switching elements Q _{1 to} Q ₆ such as MOS-FETs and bipolar transistors connected in series are connected in parallel to the power supply 12, while the switching elements Q ₁ and Q ₂ , Q ₃ and Q _{4 of} each set are connected. , Q ₅ and Q ₆ are connected to the armature coils of each phase of the motor 4. The gate driver 14 sends a gate signal to selectively turn on and off the switching element Q ₁ to Q ₆ to the gates of the switching elements Q ₁ to Q _6.
[0025]
The arithmetic processing unit 15 is configured as shown in FIG. 4 and includes a microcomputer (MPU) and various memories. In this embodiment, the magnitude and phase of the armature currents i _U , i _V , i _W supplied to the armature (stator) based on the rotation angle θ and the rotation speed v of the rotor (rotor) of the motor 4. ^{Is obtained} by calculation. That is, vector control is performed.
[0026]
The rotation angle θ and the speed v of the rotor are the position signals P (P _U , P _V , P) output from the Hall IC 16 (16U, 16V, 16W) as rotational position detectors provided for the three phases of the armature, respectively. _W )), the calculation unit 17 estimates. That is, the Hall IC 16 is provided every 60 ° in electrical angle, and any position signal P changes on and off every time the rotor rotates 60 °.
[0027]
The calculation unit 17 detects that the rotor has turned an electrical angle of 60 ° from the change of the position signal P, and detects the rotation speed v from the time interval in which the position signal P is kept constant without changing. Further, by using this rotational speed v, a rotational angle θ within a time interval during which the position signal P does not change is obtained by calculation. As a result, the rotation angle θ during rotation of the rotor can be obtained with high resolution. The calculating unit 17 obtains the vehicle speed (vehicle speed V _SP ) using the reduction ratio of the electric drive system and the diameter of the drive wheels.
[0028]
The estimated values of the rotation angle θ, the rotation speed v, and the vehicle speed V _SP obtained by the calculation unit 17 are input to the torque current calculation unit 18. The current calculation unit 18 calculates the magnitude and phase of the current command value i ₀ ^* based on the torque target value T _M obtained by the target torque calculation unit 19 and the rotation angle θ and the rotation speed v (FIG. 5). reference).
[0029]
The target torque calculator 19 obtains a target motor torque T _M based on the vehicle speed V _SP and the pedal effort T _P. For example, as shown in FIG. 4, for a vehicle speed V _SP less than a set vehicle speed (for example, 15 km / h), the assist rate (assist ratio) η (= T _M / T _P ) is set to 1.0, and this set vehicle speed ( For example, in a high speed region of 15 km / h or more, the target value of the motor torque T _M is obtained as T _M = T _P · η according to the assist rate characteristic in which the assist rate η decreases linearly as the vehicle speed V _SP increases. The auxiliary rate η becomes 0 at other set vehicle speeds (for example, 24 km / h).
[0030]
In this motor 4, the torque T _M corresponds to the actual armature current i _R (i _U , i _V , i _W ). The current calculation unit 18 obtains the magnitude and phase of the armature current i _R necessary for generating the target torque value T _M by vector calculation, and outputs it as a current command value i ₀ ^* .
[0031]
The current command value i ₀ ^* is actually output separately for each of the U, V, and W phases. That is, the current calculation unit 18 uses the sine wave pattern data stored in the memory 20 to specify current command values i ₀ ^* (i ₀ ^* _U , i ₀ ^* _V , i, whose phases are shifted from each other by 120 ° in electrical angle. ₀ ^* _W ) is output. The current command value i ₀ ^* of each phase is a sine wave whose amplitude changes depending on the magnitude of the target torque value T _M , and the amplitude and phase are calculated based on the rotation angle θ, the rotation speed v, the inertia of the rotation unit, and the like. It has been done.
[0032]
In FIG. 4, reference numeral 21 denotes a speed current calculator. The speed current calculation unit 21 calculates a motor current i _SP necessary for setting the motor rotation speed (v) corresponding to the vehicle speed V _SP when the human driving force (T _P ) is larger than the lower limit value (T _PL ). Calculate (see FIG. 5). Since the motor 4 rotates when the human driving force (T _P ) is larger than the lower limit value (T _PL ), this condition T _P > T _PL is satisfied if the signal of the vehicle speed (V _SP ) exceeds a certain level. it is conceivable that.
[0033]
22 is a follow-up current setting unit, and when the human power driving force (T _P ) is lower than the lower limit value (T _PL ) based on the motor rotation speed (v) and the human power driving force (T _P ) (T _P ≦ T _PL ), and a current necessary for driving the motor at the rotation speed (v) at this time, that is, a follow-up current (i _ID ) is calculated.
[0034]
The follower current (i _ID ) is added to the current command value (i ₀ ^* ) by the adder 23. To the added value (i ₀ ^* + i _ID ), the speed current (i _SP ) is further added in the adder 24 to obtain a final current command value i ^* (= i ₀ ^* + i _ID + i _SP ). As can be seen from FIG. 5, the current command value i ₀ ^* is a component corresponding to the pedaling force (T _P ), the speed current (i _SP ) is a component corresponding to the vehicle speed (V _SP ), and the accompanying current (i _ID ) is a component for setting the rotational speed (v) (that is, no-load rotational speed) when the pedaling force (T _P ) is zero (strictly, the lower limit value T _PL or less).
[0035]
In FIG. 4, reference numeral 25 denotes an assist stop condition determination unit. The assist stop condition determining unit 25 determines whether or not the assist stop condition is satisfied based on the human driving force (stepping force T _P ) and the motor rotation speed (v). Block _ID . The speed current i _{SP is} also cut off and the assist is stopped. On the other hand, when the pedaling force (T _P ) increases to the assist restart lower limit (T _PLR ) (however, T _PLR > T _PL ) while the follower current i _ID is being supplied, the pedaling force (T _P ) is increased to drive Because it is thought that has resumed, assist is resumed.
[0036]
When the assist is restarted (re-acceleration assist is started), for example, a method disclosed in JP-A-9-267791 can be used. That auxiliary rate target torque calculating section 19 (η _A) was smaller than the auxiliary rate of normal as determined from the auxiliary rate characteristic (eta), the auxiliary constant over time (eta _A) a predetermined time after increased gradually to Control is performed so as to match the normal auxiliary rate (η). If it does in this way, when resuming assistance during a run, the motor rotation speed will raise, the shock at the time of a one way clutch being connected can be weakened, and riding comfort can be improved.
[0037]
The final current command value i ^{* obtained} by adding the speed current (i _SP ) and the follow-up current (i _ID ) by the adders 23 and 24 is input to the subtractor 25, where the actual current value i _R of the armature and Difference (i ^* −i _R ) is obtained separately for each phase. This current value i _R is obtained by detecting the current (i _U , i _V ) of the armature's UV phase winding with a Hall CT (Current Transformer) (CT _U , CT _V ), etc. Can be calculated. This difference (i ^* −i _R ) becomes an armature current error signal and is input to the command current control unit 26. The current control unit 26 generates a gate drive signal for driving the gate of the inverter 13 by the PWM method, and sends it to the gate drive unit 14. As a result, the motor 4 is PWM-controlled to generate a target torque value T _M , and the bicycle can run by the motor output T _M and the pedaling force T _P.
[0038]
Next, the operation will be described with reference to FIGS. First, the main flow operation will be described with reference to FIG. The output of each sensor is input to the arithmetic processing unit 15 (FIGS. 2 and 3) (step S100 in FIG. 6). That is, the position signal P of the rotational position detector 16, the output signal (T _P ) of a torque sensor (not shown) for detecting the pedaling force (T _P ), the battery voltage detection signal of the battery 12 (FIGS. 2 and 3), and the like. It is digitized and input via the input interface.
[0039]
The arithmetic processing unit 15 monitors the state of charge of the battery based on the battery voltage detection signal, and displays the remaining capacity of the battery capacity on a remaining capacity display means such as an LED (step S102). The arithmetic processing unit 15 determines various operation states based on the input information, determines an operation mode corresponding to each state, and performs the processing (step S104). This processing mode includes a stop mode, a transmission mode, an auxiliary mode, a restart mode, and the like. Further, when detecting the occurrence of an abnormality from the output signal of each sensor, the arithmetic processing unit 15 performs predetermined processing at the time of abnormality such as battery protection (for example, overdischarge prevention) (step S106). Then, the above operation is repeated.
[0040]
The assist stop and assist restart operations are performed according to FIG. First, the pedaling force (T _P ) is compared with the lower limit value (T _PL ) (step S150). When T _P ≦ T _PL , follow-up control is performed (step S152). That is. The follow-up current setting unit 22 supplies the follow-up current (i _ID ) to the motor 4 from the rotation speed (v) at that time. When a certain time (for example, 0.8 seconds) elapses in this state (step S154), it is determined whether the motor rotation speed (v) is equal to or lower than a lower limit value (v _L , for example, 150 rpm) (step S156). If it is less than or equal to the lower limit value (v ≦ v _L ), it is considered that the vehicle will stop, and the assist is immediately stopped (step S158).
[0041]
If v> v _L , it is considered that the vehicle is still running without stopping (step S156), and therefore the follow-up current (i _ID ) continues to flow (step S160). If the pedaling force (T _P ) is equal to or lower than the lower limit value (T _PL ) (T _P ≦ T _PL , step S162) and the rotational speed (v) is equal to or lower than the lower limit value (v _L ) (v ≦ v _L , step S164). Since the vehicle is considered to stop, the assist is stopped (step S158). If the rotation speed (v) is larger than the lower limit value (v _L ) (step S164). Since it is considered that the vehicle is still coasting, this state is continued for a certain time (for example, 4.2 seconds) (step 166), and then the assist is stopped (step S158).
[0042]
The pedaling force (T _P ) is larger than the lower limit value (T _PL ) (T _P > T _PL , step S162) and smaller than the assist resumption lower limit value (T _PLR , where T _PLR > T _PL ) (T _P <T _PLR) In step S168), it is considered that the pedaling force (T _P ) is not increased as the acceleration is re-accelerated, and the assist is stopped after a predetermined time (for example, 4.2 seconds) has elapsed (steps S166 and S158). If the pedaling force (T _P ) is greater than the restart lower limit (T _PLR ) (step S168), it is considered that the pedaling force (T _P ) has started to increase during coasting, and re-acceleration assist is started (step S170).
[0043]
In this reacceleration assist, as described above, the auxiliary rate (η _A ) is first set to be smaller than the normal auxiliary rate (η), and is gradually increased with time to match the normal auxiliary rate (η). Is to control. If the pedal effort (T _P ) is greater than the lower limit (T _PL ) in step S150, regular assist is continued (step S172).
[0044]
【The invention's effect】
As described above, the present invention supplies the accompanying current (i _ID ) when the human driving force (T _P ) is equal to or lower than the lower limit value (T _PL ). This shortens the energy required for accelerating the motor. The assist stop condition is that the motor rotation speed (v) is lower than the lower limit value (v _L ) while the human driving force (T _P ) is lower than the lower limit value (T _PL ). When the stop condition is satisfied, the follow-up current (i _ID ) is cut off, so that it is possible to prevent wasteful consumption of the battery during coasting.
[0045]
In this case, since the assist stop condition is set using the motor rotation speed (v) without using the vehicle speed (V _SP ), the vehicle speed can be calculated from the motor rotation speed (v) without providing a separate sensor for detecting the actual vehicle speed. (V _SP ) The present invention can be applied to a vehicle that performs calculation, and the number of parts is not increased. According to the invention of claim 4 , an apparatus can be obtained which is used directly for carrying out the method of claim 1.
[Brief description of the drawings]
FIG. 1 is a diagram showing a power transmission system applied to a battery-assisted bicycle according to the present invention. FIG. 2 is an explanatory diagram of a motor control device. FIG. 3 is a diagram showing an inverter. FIG. 5 is a conceptual diagram of the operation. FIG. 6 is an operation flowchart of the main flow. FIG. 7 is an operation flowchart of assist stop / restart processing.
1 Crankshaft 4 3-phase DC non-commutator motor 8 Rear wheel (drive wheel)
10 controller 13 inverter unit 14 gate driver 15 processing unit 18 torque current calculation unit 19 target torque calculating section 21 speed current calculating unit 22 Families around the current setting portions 23, 24 adder 25 assist stop condition determining unit i _R (i _U , i _V , i _W ) Armature current P (P _U , P _V , P _W ) Position signal θ Rotational angle V _SP Vehicle speed T _P Manual driving force (stepping force)
T _PL human power lower limit T _PLR human power assist restarting the lower limit v motor rotation speed v _L motor lower limit T _M driving power of the rotational speed (motor driving force)

Claims (6)

A human power drive system and an electric drive system provided in parallel, human power (T _P) driving power for (T _M) a predetermined human power on the basis of the auxiliary rate characteristics which vary with the vehicle speed (V _SP) the ratio of In the control method of the vehicle with the electrically assisted function for generating the electric power driving force ( _TM ) according to ( _TP ),
The power source of the electric drive system is constituted by an electric motor, and when the human driving force (T _P ) is equal to or lower than the lower limit value (T _PL ), the rotational speed (v of the motor corresponding to the vehicle speed (V _SP ) at that time supplying a drag motion current (i _ID) kept), while the human power (T _P) is kept the lower limit value (T _PL) the following conditions, the motor rotational speed (v) is a lower limit value (v _L ) A control method for a vehicle with a motor-assisted function, wherein the following current (i _ID ) is cut off with the following conditions as an assist stop condition. 2. The control of a vehicle with an electric auxiliary function according to claim 1, wherein the electric motor is constituted by a DC non-commutator motor, and the motor rotational speed (v) and the vehicle speed (V _SP ) are obtained based on an output signal of the rotational position detector of the motor. Method. The assist stop condition is that the motor rotational speed (v) becomes equal to or lower than the lower limit value (v _L ) after the state where the human driving force (T _P ) is equal to or lower than the lower limit value (T _PL ) continues for a predetermined time. The method for controlling a vehicle with an electrically assisted function according to claim 1. A human power drive system and an electric drive system provided in parallel, human power (T _P) driving power for (T _M) a predetermined human power on the basis of the auxiliary rate characteristics which vary with the vehicle speed (V _SP) the ratio of In the control device for a vehicle with an electrically assisted function that generates electric power driving force ( _TM ) according to ( _TP ),
An electric motor serving as a power source for the electric drive system; a follow-up current setting unit for obtaining a follow-up current (i _ID ) based on the manpower drive force (T _P ) and the rotation speed (v) of the motor; The assist stop condition is defined as the assist stop condition that the motor speed (v) is lower than the lower limit value (v _L ) while the force (T _P ) is kept below the lower limit value (T _PL ). An assist stop condition determining unit for determining,
The control device for a vehicle with an electrically assisted function, wherein when the assist stop condition determining unit determines that an assist stop condition is satisfied, the accompanying current setting unit interrupts the accompanying current (i _ID ). In claim 4 , the electric motor is a vector-controlled DC non-commutator motor, and the motor rotational speed (v) and the vehicle speed (V _SP ) are obtained based on the output signal of the rotational position detector of the motor, A target torque calculator for obtaining a target torque (T _M ) of the motor corresponding to the vehicle speed (V _SP ) and the manpower driving force (T _P ) based on the assist rate characteristic, and a motor corresponding to this target torque (T _M ) The torque current calculation unit for obtaining the current command value (i ₀ ^* ) by vector control, and the sum of the current command value (i ₀ ^* ) and the accompanying current (i _ID ) is the final current command value (i ^* ). A control device for a vehicle with an electrically assisted function, comprising an adder. According to claim 5, human power (T _P) is a lower limit value (T _PL) from the vehicle speed when the large (V _SP) required to generate the motor rotation speed (v) corresponding to the speed the current (i _SP ) For calculating the speed current,
A vehicle with an electric auxiliary function, comprising: an adder for obtaining a final current command value (i ^* ) by calculating a sum of a current command value (i ₀ ^* ), a follow-up current (i _ID ), and the speed current (i _SP ) Control device.

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