JP2024123711A - washing machine - Google Patents

Abstract

To provide a technology capable of accurately determining whether or not a belt is cut, or whether or not the belt is out of a pulley.SOLUTION: A washing machine includes: a rotary tub for storing laundry; a pulley fixed to a rotation shaft of the rotary tub; a motor for rotating the rotary tub; a belt stretched between the motor and the pulley, and for transmitting the rotation of the motor to the rotary tub via the pulley; a current sensor for detecting a current value flowing in the motor; and a control part. The control part executes a determination process for determining whether or not the belt is cut or whether or not the belt is out of the pulley based on the current value detected by the current sensor when accelerating the motor.SELECTED DRAWING: Figure 5

Description

The technology disclosed in this specification relates to washing machines.

Patent document 1 discloses a washing machine. The washing machine in patent document 1 has a rotating drum, a drum pulley fixed to the rotating shaft of the rotating drum, a motor, a belt that transmits the rotation of the motor to the drum pulley, a current detection means that detects the current flowing through the motor, and a control means that controls the motor with reference to a predetermined target rotation speed and performs drive control and brake control to execute each process such as washing, rinsing, and spin-drying. The control means constantly calculates an induced voltage value from the output value of the current detection means while the motor is being driven, and starts brake control of the motor when the rotation speed of the motor in each process becomes higher than the target rotation speed of the motor by a predetermined value or more, and determines that the belt is broken or has come off the drum pulley based on the relationship between the value of the induced voltage generated by the motor just before brake control of the motor is performed and the time from the start of brake control until the output value of the current detection means reaches approximately zero.

Patent No. 6706738

In the technology of Patent Document 1, whether or not the belt is broken is determined based on the value when the motor is decelerated by brake control, so it is difficult to accurately determine whether or not the belt is broken. The same is true when determining whether or not the belt has come off the pulley. This specification therefore provides a technology that can accurately determine whether or not the belt is broken or whether or not the belt has come off the pulley.

The washing machine disclosed in this specification includes a spin tub that stores laundry, a pulley fixed to the rotating shaft of the spin tub, a motor for rotating the spin tub, a belt that is stretched between the motor and the pulley and transmits the rotation of the motor to the spin tub via the pulley, a current sensor that detects the value of the current flowing through the motor, and a control unit. The control unit executes a determination process that determines whether the belt is broken or whether the belt has come off the pulley based on the current value detected by the current sensor when the motor is accelerated.

FIG. 2 is a diagram showing a schematic diagram of a washing machine according to an embodiment of the present invention; FIG. 4 is a diagram showing a screen displayed on an operation panel according to the embodiment. 4 is a flowchart of a washing operation process according to an embodiment. 4 is a flowchart showing the steps of a washing operation in the embodiment. 4 is a flowchart of a determination process and a weight detection process in the first embodiment. 5 is a graph showing the rotation speed of the motor in the first embodiment. 5 is a graph showing a current value of the motor in the first embodiment. 13 is a flowchart of a determination process and a weight detection process according to a second embodiment. 13 is a graph showing the rotation speed of the motor in the second embodiment. 13 is a flowchart of a determination process and a weight detection process according to a third embodiment. 13 is a graph showing the rotation speed of the motor in the third embodiment.

The washing machine 2 of the embodiment will be described with reference to the drawings. As shown in FIG. 1, the washing machine 2 includes a housing 4, a water tub 10 disposed within the housing 4, and a spin tub 12 disposed within the water tub 10. The washing machine 2 also includes a water supply path 60 and a drainage path 64 connected to the water tub 10.

The washing machine 2 is, for example, an inclined drum type washing machine with a rotating tub 12 that is inclined relative to the horizontal. In a modified example, the washing machine 2 may be, for example, a vertical type washing machine with a pulsator that rotates in the rotating tub 12. The type of the washing machine 2 is not particularly limited. Also, in a modified example, the washing machine 2 may be a washer-dryer that can perform a drying operation to dry laundry.

The housing 4 is provided with a rotatable door 6. By rotating the door 6, the opening 102 of the water tub 10 and the opening 122 of the spin tub 12 are opened and closed. An operation panel 80 is provided on the top of the housing 4. The operation panel 80 is composed of, for example, a touch panel. The operation panel 80 can display various information related to the washing machine 2. In addition, the operation panel 80 can accept various user operations related to the washing machine 2.

As shown in FIG. 2, the operation panel 40 displays, for example, a screen SC1 for selecting a course in a washing operation. The operation panel 40 also displays, for example, a start button B1 for instructing the start of a washing operation. The screen SC1 and start button B1 shown in FIG. 2 are displayed, for example, when the power of the washing machine 2 is turned on.

The water tub 10 arranged in the housing 4 shown in FIG. 1 can store water. The rotating tub 12 arranged in the water tub 10 can store laundry. The rotating tub 12 is arranged in the water tub 10 in a rotatable state, and is driven to rotate by the motor 20. A first pulley 22 is fixed to the rotating shaft 21 of the motor 20. A second pulley 14 is fixed to the rotating shaft 13 of the rotating tub 12. A belt 24 that transmits the rotation of the first pulley 22 to the second pulley 14 is stretched between the first pulley 22 and the second pulley 14 (note that in FIG. 1, the belt 24 is highlighted in black for ease of understanding). The belt 24 transmits the rotation of the motor 20 to the rotating tub 12 via the first pulley 22 and the second pulley 14. The laundry in the rotating tub 12 is washed as the rotating tub 12 rotates.

The water supply path 60 has an upstream end connected to a water supply source (e.g., a water supply) and a downstream end connected to the aquarium 10. The water supply path 60 supplies water from the water supply source into the aquarium 10. A water supply valve 62 is provided in the water supply path 60. When the water supply valve 62 opens, water is supplied into the aquarium 10.

The drain path 64 has an upstream end connected to the aquarium 10 and a downstream end connected to a drain destination (e.g., a drain pan). The drain path 64 discharges water discharged from the aquarium 10 to the drain destination. A drain valve 66 is provided on the drain path 64. When the drain valve 66 opens, the water in the aquarium 10 is discharged to the drain destination.

The washing machine 2 further includes a current sensor 52 that detects the value of the current flowing through the motor 20, and a control unit 50. The control unit 50 includes, for example, a CPU, ROM, and RAM, and executes various controls and processes based on a predetermined program. For example, the control unit 50 controls the rotation speed of the motor 20. The control unit 50 also executes a predetermined process based on the current value detected by the current sensor 52 when the motor 20 accelerates. The controls and processes executed by the control unit 50 will be described later.

The washing machine 2 described above is capable of performing a washing operation to wash the laundry contained in the spin tub 12. In the washing operation, for example, a water supply process, a washing process, a draining process, etc. are performed. The details of the washing operation will be described later.

(Washing operation process; Figure 3)
Next, the washing operation process of the embodiment will be described. The washing operation process is started, for example, when the power supply of the washing machine 2 is turned on. As shown in FIG. 3, in S10 of the washing operation process, a course in the washing operation is selected by a user operation on the operation panel 40. The user of the washing machine 2 operates the operation panel 40 (see FIG. 2) to select a desired course (for example, a standard course) from a plurality of courses having different operation contents. The courses in the washing operation are, for example, a standard course, a speed course, a soaking course, etc. The operation contents of each course can be set appropriately. For example, the operation time of the standard course is set to be longer than the operation time of the speed course.

As shown in FIG. 3, in the next step S12, the control unit 50 determines whether or not the start button B1 is pressed when a washing operation course (e.g., the standard course) is selected on the operation panel 40 (see FIG. 2). If the start button B1 is pressed (YES in S12), the process proceeds to S14. On the other hand, if the start button B1 is not pressed (NO in S12), the process returns to S10. In S14 after YES in S12, the control unit 50 executes the washing operation.

(Washing operation; Figure 4)
Next, the washing operation of the embodiment will be described. As shown in Fig. 4, the washing operation of the embodiment includes a determination step (S20), a weight detection step (S22), a water supply step (S24), a washing step (S26), and a drainage step (S28).

The determination process (S20) is a process in which the control unit 50 determines whether the belt 24 stretched between the first pulley 22 and the second pulley 14 is broken or whether the belt 24 has come off the pulley (the first pulley 22 or the second pulley 14). The weight detection process (S22) is a process in which the control unit 50 detects the weight of the laundry contained in the spin tub 12.

(Determination process and weight detection process in the first embodiment; Figs. 5, 6, and 7)
Next, the determination process and weight detection process of the first embodiment will be described in detail. Fig. 5 is a flow chart of the determination process and weight detection process of the embodiment. The process shown in Fig. 5 is started when the washing operation is started. In S40 of this process, the control unit 50 accelerates the motor 20 for rotating the spin tub 12.

As shown in FIG. 6, when the washing operation starts, the motor 20 initially rotates at a rotation speed less than a predetermined first reference rotation speed R1. The control unit 50 then accelerates the motor 20 to increase the rotation speed of the motor 20 from a rotation speed less than the predetermined first reference rotation speed R1 (e.g., the first rotation speed X1 (e.g., 70 rpm)) to a rotation speed equal to or greater than a predetermined second reference rotation speed R2 (e.g., the second rotation speed X2 (e.g., 270 rpm)). The second reference rotation speed R2 is equal to or greater than the first reference rotation speed R1. The control unit 50 increases the rotation speed of the motor 20 from the first rotation speed X1 to the second rotation speed X2 in a time tx that is less than a predetermined reference time Tr. When the rotation speed of the motor 20 is less than the first reference rotation speed R1, the rotation speed of the rotating tub 12 is slow, so that the laundry contained in the rotating tub 12 is less likely to stick to the inner surface of the rotating tub 12. On the other hand, when the rotation speed of the motor 20 is equal to or higher than the second reference rotation speed R2, the rotation speed of the spin tub 12 is high, and the laundry stored in the spin tub 12 is likely to stick to the inner surface of the spin tub 12. The first reference rotation speed R1 is, for example, 85 rpm. The second reference rotation speed R2 is, for example, 265 rpm. The reference time Tr is, for example, 1.8 seconds. The control unit 50 may increase the rotation speed of the motor 20 as shown in graph a, as shown in graph b, or as shown in graph c. The maximum slope of the graph of the rotation speed when the motor 20 accelerates is, for example, 50 (rpm/sec) or more.

As shown in FIG. 5, in S42 following S40, the control unit 50 determines whether the current value Ix detected by the current sensor 52 when accelerating the motor 20 in S40 becomes equal to or greater than a predetermined reference current value Ir. As shown in FIG. 6 and FIG. 7, the control unit 50 determines whether the current value Ix detected by the current sensor 52 changes from less than the reference current value Ir to equal to or greater than the reference current value Ir while changing the rotation speed of the motor 20 from the first rotation speed X1 to the second rotation speed X2.

If the detected current value Ix of the current sensor 52 is equal to or greater than the reference current value Ir (YES in S42), the process proceeds to S44 (see FIG. 5). If the detected current value Ix of the current sensor 52 is less than the reference current value Ir (NO in S42), the process proceeds to S46 (see FIG. 5).

As shown in FIG. 5, in S44 after YES in S42, the control unit 50 determines that the belt 24 stretched between the first pulley 22 and the second pulley 14 is normal. The control unit 50 determines that the belt 24 is not broken and that the belt 24 has not come off the pulleys (the first pulley 22 and the second pulley 14). On the other hand, in S46 after NO in S42, the control unit 50 determines that the belt 24 is abnormal. The control unit 50 determines that the belt 24 is broken or that the belt 24 has come off the pulley (the first pulley 22 or the second pulley 14).

When the belt 24 is normal, the load for rotating the rotating tub 12 acts on the motor 20, so the motor 20 does not rotate freely and the load on the motor 20 increases, and the detected current value Ix of the current sensor 52 increases. On the other hand, when the belt 24 is abnormal, the load for rotating the rotating tub 12 does not act on the motor 20, so the motor 20 rotates freely and the load on the motor 20 does not increase, and the detected current value Ix of the current sensor 52 does not increase. Therefore, the control unit 50 can determine whether the belt 24 is broken or whether the belt 24 has come off the pulleys 22, 14 based on the current value Ix detected by the current sensor 52 when accelerating the motor 20.

In S54 following S46, the control unit 50 displays information indicating that the belt 24 is abnormal (the belt 24 is broken or the belt 24 has come off the pulleys 22, 14) on the operation panel 40. For example, the control unit 50 displays a message saying "The belt is broken" on the operation panel 40. After S54, the control unit 50 ends the washing operation process.

On the other hand, if the belt 24 is normal, in S48 after S44, the control unit 50 calculates the weight of the laundry contained in the spin tub 12. The control unit 50 calculates the weight of the laundry based on the current value Ix detected by the current sensor 52 when the motor 20 is accelerated in S40 above. The control unit 50 converts the detected current value Ix of the current sensor 52 into the weight of the laundry.

In the next step S50, the control unit 50 calculates the amount of water to be supplied to the spin tub 12 during the washing operation. The control unit 50 calculates the amount of water to be supplied based on the weight of the laundry calculated in step S48 above.

In the next step S52, the control unit 50 calculates the amount of detergent to be put into the spin tub 12 during the washing operation. The control unit 50 calculates the amount of detergent based on the weight of the laundry calculated in step S48 above. Also in step S52, the control unit 50 displays information on the calculated amount of detergent (e.g., "one cup") on the operation panel 40. This completes the determination process and weight detection process.

As shown in FIG. 4, after the determination process and the weight detection process are completed, the control unit 50 executes a water supply process (S24), a washing process (S26), and a drainage process (S28).

The water supply step (S24) is a step of supplying the amount of water calculated in S50 (see FIG. 5) above into the spin tub 12. In the water supply step (S24), the control unit 50 opens the water supply valve 62 provided in the water supply path 60. If the washing machine 2 is equipped with an automatic detergent dispenser, the control unit 50 may execute control in the water supply step (S24) to dispense the amount of detergent calculated in S52 (see FIG. 5) above into the spin tub 12 using the automatic dispenser.

The washing step (S26) shown in FIG. 4 is a step for washing the laundry contained in the spin tub 12. In the washing step (S26), the control unit 50 rotates the motor 20 at a predetermined rotation speed (e.g., 150 rpm) to rotate the spin tub 12. This causes the spin tub 12 to rotate, and the laundry in the spin tub 12 is washed with the washing liquid (a mixture of water and detergent). The predetermined rotation speed of the motor 20 in the washing step (S26) is a rotation speed smaller than the second rotation speed X2 (e.g., 270 rpm, see FIG. 6) of the motor 20 in the determination step (S20). In the determination step (S20), the control unit 50 accelerates the motor 20 to the second rotation speed X2, which is equal to or higher than the predetermined rotation speed in the washing step (S26) (see S40 in FIG. 5). At that time, the control unit 50 determines whether the belt 24 is broken or whether the belt 24 is off the pulleys 22 and 14 based on the current value Ix detected by the current sensor 52 (see S42, S44, and S46 in FIG. 5).

The drainage step (S28) shown in FIG. 4 is a step for draining the washing liquid (mixture of water and detergent) in the spin tub 12 out of the spin tub 12. In the drainage step (S28), the control unit 50 opens the drainage valve 66 provided in the drainage path 64. This ends the washing operation. Note that in the washing operation, a rinsing step and a spin-drying step may be performed after the drainage step (S28).

(effect)
The washing machine 2 of the embodiment has been described above. As is clear from the above description, in the washing machine 2 of the embodiment, the control unit 50 executes a determination process to determine whether the belt 24 is broken or whether the belt 24 is disengaged from the pulleys 22 and 14 based on the current value Ix detected by the current sensor 52 when the motor 20 is accelerated (see S40, S42, S44, and S46 in FIG. 5).

According to this configuration, when the belt 24 is not broken, the load on the motor 20 increases as the motor 20 accelerates, and the current value Ix detected by the current sensor 52 increases. This makes the value for judgment clear, so it is possible to accurately judge whether the belt 24 is broken or not. The same applies when judging whether the belt 24 has come off the pulleys 22, 14 or not.

The control unit 50 also executes a determination process (see S20 and S24 in FIG. 4) before executing a water supply process in which water is supplied into the spin tub 12 through the water supply path 60 (an example of a water supply means). With this configuration, the determination process can be executed before the laundry in the spin tub 12 gets wet. As a result, even if it is determined that the belt 24 is broken, the laundry can be removed from the spin tub 12 before it gets wet. The same applies to the case in which it is determined that the belt 24 is detached from the pulleys 22 and 14.

The control unit 50 can also execute the washing step after executing the water supply step (see FIG. 4). In the determination step (S20), the control unit 50 determines whether the belt 24 is broken or whether the belt 24 has come off the pulleys 22, 14 based on the current value Ix detected by the current sensor 52 when accelerating the motor 20 to a rotation speed equal to or higher than the rotation speed in the washing step (S26). With this configuration, by accelerating the motor 20 to a rotation speed equal to or higher than the rotation speed of the motor 20 in the washing step, the load on the motor 20 increases, so that it is possible to accurately determine whether the belt 24 is broken. The same applies to the case of determining whether the belt 24 has come off the pulleys 22, 14.

(Determination process and weight detection process in the second embodiment; Figs. 8 and 9)
Next, a second embodiment will be described. In the following, detailed description of the same configuration as the above will be omitted. FIG. 8 is a flow chart of the determination process and the weight detection process of the second embodiment. As shown in FIG. 8, in the second embodiment, the process of S60 is executed after S40. In S60, the control unit 50 stores information on the current value Ix detected by the current sensor 52 when accelerating the motor 20 in S40 in a memory. In the following S62, the control unit 50 decelerates the motor 20 accelerated in S40. As shown in FIG. 9, the control unit 50 reduces the rotation speed of the motor 20 to a rotation speed (for example, a first rotation speed X1) that is less than the first reference rotation speed R1.

In the next step S64, the control unit 50 accelerates the motor 20 again after it was decelerated in S62. The control unit 50 increases the rotation speed of the motor 20 from a rotation speed less than the first reference rotation speed R1 (e.g., the first rotation speed X1) to a rotation speed equal to or greater than the second reference rotation speed R2 (e.g., the second rotation speed X2). The control unit 50 increases the rotation speed of the motor 20 from the first rotation speed X1 to the second rotation speed X2 in a time tx that is less than the reference time Tr.

In the next S66, the control unit 50 stores in memory information on the current value Ix detected by the current sensor 52 when accelerating the motor 20 in S64 above. In the next S142, the control unit 50 determines whether the average value of the detected current value Ix stored in memory in S60 above and the detected current value Ix stored in memory in S66 above is equal to or greater than the reference current value Ir. If the average value of the detected current value Ix is equal to or greater than the reference current value Ir (YES in S142), the process proceeds to S44. If the average value of the detected current value Ix is less than the reference current value Ir (NO in S42), the process proceeds to S46.

As described above, in the second embodiment, the control unit 50 executes acceleration control to accelerate the motor 20 multiple times, and executes a determination process to determine whether the belt 24 is broken or whether the belt 24 has come off the pulleys 22 and 14 based on the current value Ix detected by the current sensor 52 during the multiple acceleration controls.

With this configuration, by making a judgment based on multiple detected current values Ix, it is possible to accurately determine whether or not the belt 24 is broken. The same is true for whether or not the belt 24 has come off the pulleys 22, 14.

(Modification)
In the second embodiment described above, the acceleration control for accelerating the motor 20 is executed twice, but the present invention is not limited to this configuration. In a modified example, the control unit 50 may execute the acceleration control for accelerating the motor 20 three or more times. In this case, the control unit 50 determines whether the belt 24 is broken or not based on the average value of the current value Ix detected by the current sensor 52 in the three or more acceleration controls. The same applies to whether the belt 24 is off the pulleys 22, 14 or not.

(Determination process and weight detection process in the third embodiment; Figs. 10 and 11)
Next, a third embodiment will be described. In the following, detailed description of the same configuration as the above will be omitted. FIG. 10 is a flow chart of the determination process and the weight detection process of the third embodiment. As shown in FIG. 10, in the third embodiment, the process of S80 is executed after S40. In S40, the control unit 50 accelerates the motor 20 in the forward rotation direction. The forward rotation direction is, for example, the direction in which the rotating shaft 21 of the motor 20 rotates clockwise. In the following S80, the control unit 50 stores in memory information on the current value Ix detected by the current sensor 52 when accelerating the motor 20 in the forward rotation direction in S40.

In the next step S82, the control unit 50 accelerates the motor 20 in the reverse direction. The reverse direction is, for example, the direction in which the rotating shaft 21 of the motor 20 rotates counterclockwise. As shown in FIG. 11, the control unit 50 increases the rotation speed of the motor 20 in the reverse direction from a rotation speed less than the first reference rotation speed R1 (for example, the first rotation speed X1) to a rotation speed equal to or greater than the second reference rotation speed R2 (for example, the second rotation speed X2). The control unit 50 increases the rotation speed of the motor 20 in the reverse direction from the first rotation speed X1 to the second rotation speed X2 in a time tx that is less than the reference time Tr.

In the next S84, the control unit 50 stores in memory information on the current value Ix detected by the current sensor 52 when accelerating the motor 20 in the reverse direction in S82 above. In the next S142, the control unit 50 determines whether the average value of the detected current value Ix stored in memory in S80 above and the detected current value Ix stored in memory in S84 above is equal to or greater than the reference current value Ir. If the average value of the detected current value Ix is equal to or greater than the reference current value Ir (YES in S142), the process proceeds to S44. If the average value of the detected current value Ix is less than the reference current value Ir (NO in S42), the process proceeds to S46.

As described above, in the third embodiment, the control unit 50 executes a first acceleration control (S40) that accelerates the motor 20 in the forward direction and a second acceleration control (S82) that accelerates the motor 20 in the reverse direction, and determines whether the belt 24 is broken or not based on the current value Ix detected by the current sensor 52 during the first acceleration control and the second acceleration control. The same applies to whether the belt 24 is off the pulleys 22, 14.

With this configuration, it is possible to accurately determine whether the belt 24 is broken by determining whether the belt 24 is broken based on the detected current value Ix when the motor 20 is rotating in the forward direction and the detected current value Ix when the motor 20 is rotating in the reverse direction. The same applies to whether the belt 24 is off the pulleys 22 and 14.

(Modification)
In a modification of the third embodiment, the control unit 50 may execute the first acceleration control for accelerating the motor 20 in the forward rotation direction two or more times. Also, the control unit 50 may execute the second acceleration control for accelerating the motor 20 in the reverse rotation direction two or more times. In this case, the control unit 50 determines whether the belt 24 is broken or not based on the average value of the detected current value Ix of the current sensor 52 in two or more first acceleration controls and the detected current value Ix of the current sensor 52 in two or more second acceleration controls. The same applies to whether the belt 24 is off the pulleys 22, 14.

Although specific examples of the present invention have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exert technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of those objectives is itself technically useful.

2: washing machine, 4: housing, 10: water tub, 12: rotating tub, 14: second pulley, 20: motor, 22: first pulley, 24: belt, 40: operation panel, 50: control unit, 52: current sensor, 60: water supply path, 64: drainage path, 80: operation panel

Claims (5)

A rotating tub for storing laundry;
A pulley fixed to a rotation shaft of the rotating tank;
A motor for rotating the rotating tub;
a belt that is stretched between the motor and the pulley and transmits the rotation of the motor to the rotating tub via the pulley;
a current sensor for detecting a value of a current flowing through the motor;
A control unit,
The control unit executes a determination process to determine whether or not the belt is broken or whether or not the belt has come off the pulley based on the current value detected by the current sensor when accelerating the motor. The water supply means further includes a water supply means for supplying water into the rotating tank.
The washing machine according to claim 1 , wherein the control unit executes the determination step before executing a water supply step in which the water supply means supplies water into the spin tub. The washing machine according to claim 2, wherein the control unit is capable of executing a washing process for washing the laundry in the spin tub by rotating the motor at a predetermined rotation speed after executing the water supply process, and in the determination process, determines whether the belt is broken or whether the belt is dislodged from the pulley based on the current value detected by the current sensor when the motor is accelerated to a rotation speed equal to or higher than the predetermined rotation speed. The washing machine according to claim 1, wherein the control unit executes acceleration control for accelerating the motor multiple times, and in the determination process, determines whether the belt is broken or whether the belt is disengaged from the pulley based on the current value detected by the current sensor during the multiple acceleration controls. The washing machine according to claim 1, wherein the control unit executes a first acceleration control for accelerating the motor in a forward rotation direction and a second acceleration control for accelerating the motor in a reverse rotation direction, and in the determination process, the control unit determines whether the belt is broken or whether the belt is disengaged from the pulley based on the current value detected by the current sensor during the first acceleration control and the second acceleration control.

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