JP2011046326A - Coaxial motorcycle and method of controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coaxial motorcycle and a method of controlling the same capable of shifting the coaxial motorcycle to a safe state when an angle sensor fails so that a passenger can safely descend. <P>SOLUTION: The coaxial motorcycle is equipped with a plurality of coaxially arranged wheels, and runs while performing an inverse pendulum control. The coaxial motorcycle includes: a motor 321 for driving the plurality of wheels; an angle sensor 430 for detecting a rotation angle of the motor 321; and an angle estimation section 630 for estimating the rotation angle of the motor based on the driving current of the motor 321. When the angle sensor 430 fails, the motor drive control using the angle sensor 430 is switched to the motor drive control using an output value from the angle estimation section 630, and the motor drive control is performed according to the rotation speed of the motor 321 when the angle sensor 430 fails. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a coaxial two-wheeled vehicle and a control method therefor, and more particularly to a coaxial two-wheeled vehicle that can be shifted to a safe state when an angle sensor fails and a control method therefor.

  A coaxial two-wheeled vehicle as shown in FIG. 6 is known. The coaxial two-wheeled vehicle includes a pair of coaxial wheels driven by an electric motor, and travels while maintaining a balance in a state where a person gets on the step in a standing posture. In such a coaxial two-wheeled mobile robot, in order to run while maintaining an inverted state, motor drive control is performed using an angle sensor (such as a rotary encoder) that detects a rotation angle of a wheel (for example, Patent documents 1 to 3).

  The motor mounted on the coaxial two-wheeled vehicle requires particularly precise drive control. The drive control of the motor is performed based on a signal from an angle sensor provided in the motor. For this reason, when the angle sensor fails, processing such as stopping the driving of the motor is performed.

  On the other hand, there is also a method for driving and controlling a motor without using an angle sensor. However, since the precision of driving is insufficient for use in a coaxial two-wheeled vehicle, it is not usually used in a coaxial two-wheeled vehicle.

Japanese Patent Laid-Open No. 2005-6435 Japanese Patent Laid-Open No. 2005-94858 JP 2005-145293 A

  However, in the conventional coaxial two-wheeled vehicle described in Patent Document 1 or the like, if the motor is stopped when an angle sensor provided in the motor fails, inconvenience may occur in the operation of the coaxial two-wheeled vehicle.

  For example, when a coaxial two-wheeled vehicle travels, if the angle sensor breaks down during traveling as shown in FIG. For this reason, the vehicle may fall forward and the occupant may fall.

  Therefore, the present invention solves the above-described problems, and provides a coaxial two-wheeled vehicle and a control method therefor that enable a passenger to safely get off by shifting the coaxial two-wheeled vehicle to a safe state when an angle sensor fails. The purpose is to provide.

  A coaxial two-wheeled vehicle according to the present invention is a coaxial two-wheeled vehicle that includes a plurality of wheels arranged on the same axis and travels while performing an inversion control, and a motor that drives the plurality of wheels, and a rotation angle of the motor. An angle sensor for detecting, and an angle estimator for estimating a rotation angle of the motor from a drive current of the motor, and when the angle sensor fails, the angle is detected from the motor drive control using the angle sensor. Switching to motor drive control using an output value from the estimation unit is performed, and motor drive control is performed according to the rotational speed of the motor when the angle sensor fails.

  Thereby, even when an angle sensor breaks down, a coaxial two-wheeled vehicle can be changed to a safe state, and a passenger | crew can get off safely.

  A control method of a coaxial two-wheeled vehicle according to the present invention includes a plurality of wheels arranged coaxially, a motor that drives the plurality of wheels, and an angle sensor that detects a rotation angle of the motor, and performs an inverted control. A control method for a coaxial two-wheeled vehicle that travels while executing, and when a failure of the angle sensor is detected, motor drive control using the angle sensor is performed by estimating a rotation angle of the motor from a drive current of the motor. Switching to the motor drive control using the value obtained in this manner, determining whether the rotational speed of the motor at the time of failure of the angle sensor is equal to or higher than a predetermined specified value, and the rotational speed of the motor is a predetermined specified value In the above case, the motor drive control is continuously performed using the estimated value.

  Thereby, even when an angle sensor breaks down, a coaxial two-wheeled vehicle can be changed to a safe state, and a passenger | crew can get off safely.

  ADVANTAGE OF THE INVENTION According to this invention, when an angle sensor fails, a coaxial two-wheeled vehicle can be changed to a safe state, and the coaxial two-wheeled vehicle which a passenger | crew can get off safely and its control method can be provided.

1 is a configuration diagram of a control system for a coaxial two-wheeled vehicle according to Embodiment 1. FIG. 1 is a configuration diagram of a motor driver according to Embodiment 1. FIG. FIG. 2 is a flowchart showing a control method for the coaxial two-wheeled vehicle according to the first embodiment. It is a figure which shows the control operation of a coaxial two-wheeled vehicle when the angle sensor which concerns on Embodiment 1 fails. It is a figure which shows the control operation of a coaxial two-wheeled vehicle when the angle sensor which concerns on Embodiment 1 fails. 1 is a diagram showing an external configuration of a coaxial two-wheeled vehicle according to a first embodiment. It is a figure for demonstrating the subject of this invention.

Embodiment 1 FIG.
Embodiments of the present invention will be described below with reference to the drawings. The external configuration of the coaxial two-wheeled vehicle according to the present embodiment is the same as that illustrated in FIG. That is, as shown in FIG. 6, the coaxial two-wheeled vehicle 300 includes a vehicle main body 310, a pair of left and right wheels 320 and 320, and an operation lever 330. The pair of wheels 320, 320 are disposed on both sides in a direction orthogonal to the traveling direction of the vehicle body 310 and are disposed coaxially with each other. Further, the pair of wheels 320 and 320 are rotatably supported by the vehicle main body 310. The wheels 320 and 320 are connected to a motor via a speed reducer (not shown).

  In the following description, an axis corresponding to the axles of the pair of wheels 320 and 320 will be referred to as a pitch axis, and an axis parallel to the traveling direction of the coaxial two-wheeled vehicle 300 through the center of the vehicle body 310 will be described as a roll axis.

  On the upper surface of the vehicle main body 310, two step portions 311 for respectively placing the passenger's feet are provided. An operation lever 330 is attached to the vehicle main body 310. The operation lever 330 is attached to the vehicle main body 310 so as to be rotatable in the roll axis rotation direction. Here, when the operation lever 330 is inclined in the pitch axis rotation direction (front-rear direction), the forward or backward operation of the coaxial two-wheeled vehicle 300 is executed, and when the operation lever 330 is inclined in the roll axis rotation direction (left-right direction), A turning operation is performed.

  FIG. 1 is a configuration diagram showing a control system for a coaxial two-wheeled vehicle. As illustrated in FIG. 1, the coaxial two-wheeled vehicle 300 includes a pair of motors 321 and 321, a pair of motor drivers 322 and 322, a posture sensor 410, a handle sensor 420, angle sensors 430 and 430, and a control device 500. And.

  The attitude sensor 410 is disposed in the vehicle main body 310 and detects a pitch angle, a pitch angular velocity, an acceleration, and the like of the vehicle main body 310 when the coaxial two-wheeled vehicle 300 travels. The posture sensor 410 is composed of, for example, a gyro sensor, an acceleration sensor, and the like.

  When the operation lever 330 is tilted forward or backward, the vehicle main body 310 is also tilted in the same direction in conjunction with the operation lever 330. The posture sensor 410 detects the pitch angle and pitch angular velocity (posture value) of the vehicle main body 310 corresponding to the inclination of the operation lever 330. A sensor signal from the attitude sensor 410 is output to the control device 500.

  The handle sensor 420 is attached to the rotation shaft of the operation lever 330. As the handle sensor 420, for example, a potentiometer, a sensor having a variable capacitor structure, or the like can be applied. The handle sensor 420 detects the operation amount and the operation direction when the operation lever 330 is rotated in the direction in which the passenger wants to turn. When the operation lever 330 is operated, the handle sensor 420 outputs an operation signal corresponding to the operation amount and the operation direction to the control device 500.

  The angle sensors 430 and 430 are respectively disposed on the left and right motors 321 and 321 and detect the rotation angles of the motors 321 and 321 (that is, the rotation angles of the wheels 320 and 320), respectively. The angle sensors 430 and 430 output the detected wheel rotation angles of the wheels 320 and 320 to the motor drivers 322 and 322, respectively. As the angle sensors 430 and 430, for example, a rotary sensor or a resolver can be used. These sensors may be configured to include only one type of sensor, or may be configured to include two types of sensors.

  The pair of motor drivers 322 and 322 are built in the vehicle main body 310 and drive the left and right motors 321 and 321, respectively. As the motor 321, a DC brushless motor can be used. The motor drivers 322 and 322 are supplied with power from a battery (not shown). The motor drivers 322 and 322 generate drive currents for the motors 321 and 321 using the supplied power as a power source.

  The control device 500 drives and controls the motors 321 and 321 via the motor drivers 322 and 322. The control device 500 includes a CPU (Central Processing Unit) that performs arithmetic processing, a ROM (Read Only Memory) that stores a control program executed by the CPU, an arithmetic program, and a RAM (temporarily storing processing data). Random Access Memory), etc., and a traveling control function.

  Based on the pitch angle and pitch angular velocity of the vehicle main body 310 detected by the attitude sensor 410, the control device 500 calculates the tilt direction (forward or backward) of the operation lever 330 and the corresponding traveling speed. And the control apparatus 500 controls motor drive so that the coaxial two-wheeled vehicle 300 moves with the calculated inclination direction and moving speed, maintaining the balance of the coaxial two-wheeled vehicle 300. As a result, the coaxial two-wheeled vehicle 300 can move forward or backward at a desired traveling speed while executing an inverted control that maintains a balance. Further, the control device 500 controls the driving of the pair of motors 321 and 321 in accordance with an operation signal from the handle sensor 420, and causes a difference in rotation between the left and right wheels 320 and 320. Thereby, the coaxial two-wheeled vehicle 300 turns in a desired direction at a desired speed.

  FIG. 2 is a diagram showing a more detailed configuration of the motor driver. As illustrated in FIG. 2, the motor driver 322 includes a current control device 610, an inverter 620, an angle estimation unit 630, and a switching unit 640.

  The current control device 610 calculates and creates a current command value that flows through the coil of the motor 321 in accordance with the control command value from the control device 500. The current control device 610 performs feedback control on the control command value output by the control device 500 using the detection value based on the detection value of the angle sensor 430 or the output value of the angle estimation unit 630. The current control device 610 calculates the rotational speed of the motor 321 from the detection value of the angle sensor 430, and calculates the estimated value of the rotational speed of the motor 321 from the output value of the angle estimation unit 630. The control command value output from the control device 500 may be, for example, a speed command value of the rotational angular velocity of the wheel or a torque command value.

  The inverter 620 performs PWM (Pulse Width Modulation) control based on the current command value from the current control device 610 and supplies the drive current divided into the three phases to the motor 321.

  When the angle sensor 430 fails, the angle estimation unit 630 detects the drive current of the motor 321 and estimates the rotation angle of the motor based on the detected drive current waveform of the motor 321 and the like. Specifically, for example, the angle estimation unit 630 can detect the rotational position of the rotor from the induced voltage generated in the stator coil due to the rotation of the rotor magnet of the motor 321. As a method for detecting the rotational position of the rotor in the motor driver 322, for example, literature (Kenji Sakamoto, Yukihiko Okamura, Nao Arimura, Hiroshi Miyazaki, “Sensorless control of brushless motor for charging command electric tool”, Matsushita Electric Works, Ltd. Technical Report, Matsushita Electric Works, Ltd., November 2004, Vol. 52, No. 4, p. The angle estimation method by the angle estimation unit 630 is not limited to this, and other known techniques can be used.

  When the angle sensor 430 fails, the switching unit 640 switches from the control operation using the detection value of the angle sensor 430 to the control operation using the estimated value of the angle estimation unit 630. Here, the function of the switching unit 640 is realized by software.

  Next, the control operation of the coaxial two-wheel vehicle will be described with reference to FIGS. FIG. 3 is a flowchart showing a control operation method of the coaxial two-wheeled vehicle including a case where the angle sensor fails.

  First, during normal traveling, the current control device 610 performs failure determination of the angle sensor 430 (S101). The current control device 610 determines a failure of the angle sensor 430 based on the output value of the angle sensor 430. Various methods can be adopted as a failure determination method of the angle sensor 430. For example, the failure of the angle sensor 430 can be determined by comparing the detection value of the angle sensor 430 with a reference value obtained from the operation state of the coaxial two-wheeled vehicle detected from the attitude sensor 410. Further, a plurality of sensors of different types may be mounted as the angle sensor 430, and the failure may be determined by comparing the detected values with each other, or a failure may be determined by mounting a plurality of sensors of the same type. Good. The angle sensor failure determination method is not limited to this, and other known techniques can be used.

  Next, when a failure of the angle sensor 430 is detected (Yes in step S101), the current control device 610 determines whether or not the rotation speed of the motor 321 is equal to or higher than a specified value (step S102). . Here, the determination of the rotation speed of the motor 321 when the angle sensor 430 fails may be performed using the detection value at the detection timing immediately before the failure determination.

  Next, when the rotation speed of the motor 321 is equal to or higher than the specified value (Yes in step S102), the current control device 610 controls the motor 321 using the estimated value by the angle estimating unit 630 ( Step S103). That is, when the current control device 610 detects a failure of the angle sensor 430, the current control device 610 operates the switching unit 640 to change from the control operation using the angle sensor 430 to the control operation using the angle estimation unit 630. Switch. Thereby, the current control device 610 controls the motor 321 based on the normal control command value for the inversion and traveling control and the estimated value by the angle estimating unit 630.

  As shown in FIG. 4, in the coaxial two-wheeled vehicle according to the first embodiment, the angle sensor 430 fails when the coaxial two-wheeled vehicle is traveling at a high speed (that is, when the rotational speed of the motor 321 is equal to or higher than a specified value). In such a case (FIG. 4A), the driving of the motor 321 is continued using the estimated value by the angle estimation unit 630 (FIG. 4B). Then, after the coaxial two-wheeled vehicle is shifted to a safe state and the deceleration / alighting function is executed, the driving of the motor 321 is stopped (FIG. 4C). Thereby, even when the angle sensor 630 breaks down, the occupant can get off safely.

  In step S102, when the rotation speed of the motor 321 is smaller than the specified value (No in step S102), the current control device 610 stops or fixes the driving of the motor 321 (step S104). The current control device 610 outputs to the motor 321 a drive current that stops driving the motor 321 or a drive current that does not rotate the motor 321. Here, the drive current that does not rotate the motor 321 means a current that does not switch the phase of the current supplied to the motor 321. By supplying such a drive current to the motor 321, the motor 321 is braked.

  As shown in FIG. 5, the coaxial two-wheeled vehicle according to the first embodiment is in a state where the coaxial two-wheeled vehicle is traveling at a very low speed or in a stationary state (that is, a situation where the rotational speed of the motor 321 is smaller than a specified value). When the angle sensor 430 fails (FIG. 5A), the driving of the motor 321 is stopped or fixed (FIG. 5B). Here, since the speed of the coaxial two-wheeled vehicle is not output, it is possible to easily get off the vehicle (FIG. 5C). Thereby, even when the angle sensor 630 breaks down, the passenger can get off safely.

  If no failure of the angle sensor 430 is detected in step S101 (No in step S101), the current control device 610 drives the motor 321 using the detection value from the angle sensor 430 (step S105). . That is, the current control device 610 controls the motor 321 based on a normal control command value for inversion and traveling control and a value detected by the angle sensor 430.

  For example, when the coaxial two-wheeled vehicle is in a stationary state on the spot, the motor 321 used by the coaxial two-wheeler for the inversion control performs control to finely switch between normal rotation and reverse rotation. In order to smoothly execute this switching by the motor 321, it is necessary to measure the rotation angle of the motor 321 with high accuracy using the angle sensor 430 and to perform drive control of the motor 321 based on the measured value.

  On the other hand, in a situation where the motor 321 is rotating to some extent quickly, such as when the coaxial two-wheeled vehicle is running, high accuracy is not required for the rotation angle obtained from the measurement value of the angle sensor 430. For example, the motor 321 Even if the control is performed using the rotation angle of the motor 321 estimated from the drive current waveform or the like, there is no significant problem with respect to the control operation during traveling.

  Accordingly, by combining these characteristics, the coaxial two-wheeled vehicle according to the present embodiment can not be operated unless the value of the angle sensor 430 is used when the angle sensor 430 provided in the motor 321 fails. (For example, when driving at an extremely low speed), the rotation of the motor 321 is fixed by stopping the driving of the motor 321 or passing a current that does not rotate the motor 321. This is because when the motor 321 is operating at a very low speed, the speed of the coaxial two-wheeled vehicle is not obtained even if the motor 321 is stopped immediately in response to detection of a failure of the angle sensor 430. This is because passengers are often able to ensure safety.

  On the other hand, in a situation where the motor 321 cannot be stopped immediately when the angle sensor 430 fails, the motor 321 often rotates at a high speed. For this reason, the coaxial two-wheeled vehicle according to the present embodiment is as described above when the motor 321 rotates at high speed (for example, when traveling at high speed) when the angle sensor 430 fails. In addition, even if the value of the angle sensor 430 is not used, even if it is based on the rotation angle estimated from the drive current value of the motor or the like, it is an area where the control can be executed sufficiently to the extent that it does not hinder the running. Therefore, the drive control of the motor 321 is executed based on the estimated value of the rotation angle for the section when the motor 321 of the coaxial two-wheeled vehicle is rotating at a high speed to the safe state for the occupant. be able to.

  As described above, according to the present invention, when the angle sensor 430 fails, the motor drive control using the angle sensor 430 is switched to the motor drive control using the output value from the angle estimation unit 630. By performing motor drive control in accordance with the rotation speed of the motor when the angle sensor 430 fails, the coaxial two-wheeled vehicle can be shifted to a safe state when the angle sensor fails, and the passenger can safely get off. .

  In addition, this invention is not limited to each embodiment mentioned above, In the range which does not deviate from the meaning, it can change suitably.

300 Coaxial motorcycle 310 Vehicle body,
311 steps,
320 wheels,
321 motor,
322 motor driver,
330 operation lever,
410 attitude sensor,
420 handle sensor,
430 angle sensor,
500 controller,
610 flow control device,
620 inverter,
630 angle estimation unit,
640 switching unit,

Claims (5)

A coaxial two-wheeled vehicle having a plurality of wheels arranged on the same axis and running while performing an inverted control,
A motor for driving the plurality of wheels;
An angle sensor for detecting a rotation angle of the motor;
An angle estimation unit that estimates the rotation angle of the motor from the drive current of the motor,
When the angle sensor fails, the motor drive control using the angle sensor is switched to the motor drive control using the output value from the angle estimation unit, and the rotation speed of the motor when the angle sensor fails A coaxial two-wheeled vehicle that performs motor drive control according to the motor. When the angle sensor fails and the rotational speed of the motor at the time of failure of the angle sensor is equal to or greater than a predetermined value,
The coaxial two-wheeled vehicle according to claim 1, wherein motor drive control is continuously performed using an output value from the angle estimation unit. When the rotation speed of the motor at the time of failure of the angle sensor is smaller than a predetermined specified value when the angle sensor fails,
The coaxial two-wheeled vehicle according to claim 2, wherein motor drive control is performed so as to stop or fix the drive of the motor. The coaxial motor according to any one of claims 1 to 3, wherein the motor is a brushless motor. A control method for a coaxial two-wheeled vehicle that includes a plurality of wheels arranged on the same axis, a motor that drives the plurality of wheels, and an angle sensor that detects a rotation angle of the motor, and that runs while performing an inverted control. There,
When a failure of the angle sensor is detected, the motor drive control using the angle sensor is switched to motor drive control using a value obtained by estimating the rotation angle of the motor from the drive current of the motor,
It is determined whether or not the rotation speed of the motor at the time of the failure of the angle sensor is equal to or higher than a predetermined specified value. If the rotation speed of the motor is equal to or higher than a predetermined specified value, the estimated obtained value A method for controlling a coaxial two-wheeled vehicle, characterized in that motor drive control is continuously performed using a motor.

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