tipper
#custom circuits
#electric wheelchair motors
#scrap metal
#surplus battery
#controller circuit
Description: A Tipper was constructed for $45 in parts, utilizing salvaged components from a broken electric wheelchair, scrap metal, and a surplus battery obtained from a garage sale. The system comprises three primary components: a controller circuit with sensors (gyroscope and accelerometers), a dual H-bridge motor controller, and the mechanical assembly including the drive motors. The Tipper is managed by a microcontroller that continuously reads sensor data and commands the motor controllers. The objective is to maintain the handlebars in an upright position. When the rider leans forward, the Tipper accelerates forward; when leaning backward, the motors reverse to maintain balance. The controller estimates the tilt using accelerometer and gyroscope data, employing a combination of software low-pass and high-pass filters to mitigate inaccuracies. The accelerometer provides long-term tilt estimates, while the gyroscope offers short-term measurements. The system integrates these readings to determine the current tilt, allowing the controller to command variable motor speeds through a PID control loop, which stabilizes the Tipper. The dual H-bridge motor controller regulates voltage to the drive motors, effectively functioning as speed controllers.
The Tipper's design integrates several key components that work synergistically to achieve the desired balance and control. The microcontroller serves as the brain of the system, executing a control algorithm that continuously monitors the tilt of the device. The gyroscope and accelerometer are critical sensors; the gyroscope measures the rate of rotation, while the accelerometer detects the tilt angle by measuring gravitational forces. The combination of these sensors allows the system to estimate the tilt with greater accuracy than either sensor could provide alone.
The algorithm implemented in the microcontroller employs a complementary filter approach, merging the outputs of the accelerometer and gyroscope. The low-pass filter applied to the accelerometer readings helps to smooth out the noise from rapid accelerations, while the high-pass filter on the gyroscope readings helps to counteract drift over time. This dual filtering process ensures that the tilt estimation remains stable and responsive to changes in orientation.
Once the tilt is determined, the microcontroller calculates the necessary adjustments to the motor speeds through the PID control loop. This control loop is essential for maintaining the balance of the Tipper, as it continuously adjusts the motor speeds based on the difference between the desired upright position and the current tilt. The proportional, integral, and derivative components of the PID controller work together to minimize this error, ensuring that the Tipper remains stable even as the rider shifts their weight.
The dual H-bridge motor controller plays a crucial role in translating the microcontroller's commands into physical movement. By controlling the voltage supplied to the DC motors, the H-bridge allows for precise speed regulation, enabling the Tipper to respond quickly to the rider's movements. The use of MOSFETs in the H-bridge design provides efficient switching, reducing power loss and enhancing the overall performance of the system.
In conclusion, the Tipper's design exemplifies the integration of various electronic components and control systems to achieve a functional and responsive balancing mechanism. The careful calibration of the control loop and the effective use of sensor data are fundamental to the successful operation of this innovative device.I decided to make one for $45 in parts. Judging from the components I ended up using, one can tell. The motors and tires were salvaged from a broken electric wheelchair, the metal was scrap, the battery surplus from a garage sale, all the circuits custom-made. The system has three primary components: a controller circuit and its sensors (gyroscope and accelerometers), a dual H-bridge motor controller, and the mechanical assembly including the drive motors. The Tipper is controlled by a microcontroller that runs through a loop several hundred times per second reading in sensor data and then commanding two H-Bridge motor controllers.
The objective is to always keep the handlebars close to upright. When this invariant is held true, if one leans forward the Tipper will accelerate forward to compensate and keep the handlebars upright. If one leans backward, the Tipper will turn the motors on in reverse to compensate in the opposite direction.
This is precisely the desired operation, and it is how the Tipper is controlled. If the rider wants to go forward, just lean forward. In order to do this, the controller needs to know the current tilt of the device. It uses accelerometer and gyroscope data to estimate the physical state of the system. Unfortunately, there is not a reliable tilt sensor that is resistant to offset from acceleration of the entire device, so the controller needs to estimate the tilt with the two sensors it has. The (simplified) intuition behind how this works is that the accelerometer gives a very good long-term estimate on tilt, but is rather poor for any single measurement, whereas the gyroscope is very effective for short-term measurements, but is inaccurate for the long-term.
The algorithm it uses to estimate tilt is essentially a combination of an accelerometer with a software "low pass filter" and a gyroscope with a software "high-pass filter. " The theory is as follows: in the long run an accelerometer can read the component of gravity acting on it.
When the device is completely horizontal, there is no gravity acting on the axis of measurement because gravity is therefore orthogonal to the Tipper. When straight up, the component of gravity is a full 9. 8 m/s. A software low pass filter is used to partially filter out the "noise" caused by the sensor reading the forward and backward acceleration of the Tipper and misinterpreting it as gravity.
There is a high-pass filter on the gyroscope because it is prone to integration drift. The gyroscope is not a tilt sensor, it is a rate of tilt sensor. To get changes in tilt, the controller integrates the data coming from the gyroscope. Over time, small errors accumulate making the estimated position increasingly incorrect. To account for this drift, a software high pass filter biases recent data from the gyroscope. When weighted and then combined, they give a fairly accurate estimate on the Tipper`s tilt. With the current system state (the tilt) now known, and the desired state a constant (upright the Tipper at all times), the controller can now command the motor speed controllers. The speed controllers are variable, which means the controller must choose a desired velocity for the motors and send that request to the speed controllers.
A PID (proportional, integral, derivative) control loop is used to pick the correct motor velocity in order to close the difference between the desired and current system state. The scale factors used in this control loop are very sensitive to changes. It took a great deal of time to fine tune the control loop to effectively stabilize the physical system.
The Tipper uses a custom dual H-bridge motor controller to regulate voltage to the two drive motors. Since voltage sets speed on a DC motor, these are effectively speed controllers. The H-bridge uses mosfets to switch current on and off the motors at a v
The Tipper's design integrates several key components that work synergistically to achieve the desired balance and control. The microcontroller serves as the brain of the system, executing a control algorithm that continuously monitors the tilt of the device. The gyroscope and accelerometer are critical sensors; the gyroscope measures the rate of rotation, while the accelerometer detects the tilt angle by measuring gravitational forces. The combination of these sensors allows the system to estimate the tilt with greater accuracy than either sensor could provide alone.
The algorithm implemented in the microcontroller employs a complementary filter approach, merging the outputs of the accelerometer and gyroscope. The low-pass filter applied to the accelerometer readings helps to smooth out the noise from rapid accelerations, while the high-pass filter on the gyroscope readings helps to counteract drift over time. This dual filtering process ensures that the tilt estimation remains stable and responsive to changes in orientation.
Once the tilt is determined, the microcontroller calculates the necessary adjustments to the motor speeds through the PID control loop. This control loop is essential for maintaining the balance of the Tipper, as it continuously adjusts the motor speeds based on the difference between the desired upright position and the current tilt. The proportional, integral, and derivative components of the PID controller work together to minimize this error, ensuring that the Tipper remains stable even as the rider shifts their weight.
The dual H-bridge motor controller plays a crucial role in translating the microcontroller's commands into physical movement. By controlling the voltage supplied to the DC motors, the H-bridge allows for precise speed regulation, enabling the Tipper to respond quickly to the rider's movements. The use of MOSFETs in the H-bridge design provides efficient switching, reducing power loss and enhancing the overall performance of the system.
In conclusion, the Tipper's design exemplifies the integration of various electronic components and control systems to achieve a functional and responsive balancing mechanism. The careful calibration of the control loop and the effective use of sensor data are fundamental to the successful operation of this innovative device.I decided to make one for $45 in parts. Judging from the components I ended up using, one can tell. The motors and tires were salvaged from a broken electric wheelchair, the metal was scrap, the battery surplus from a garage sale, all the circuits custom-made. The system has three primary components: a controller circuit and its sensors (gyroscope and accelerometers), a dual H-bridge motor controller, and the mechanical assembly including the drive motors. The Tipper is controlled by a microcontroller that runs through a loop several hundred times per second reading in sensor data and then commanding two H-Bridge motor controllers.
The objective is to always keep the handlebars close to upright. When this invariant is held true, if one leans forward the Tipper will accelerate forward to compensate and keep the handlebars upright. If one leans backward, the Tipper will turn the motors on in reverse to compensate in the opposite direction.
This is precisely the desired operation, and it is how the Tipper is controlled. If the rider wants to go forward, just lean forward. In order to do this, the controller needs to know the current tilt of the device. It uses accelerometer and gyroscope data to estimate the physical state of the system. Unfortunately, there is not a reliable tilt sensor that is resistant to offset from acceleration of the entire device, so the controller needs to estimate the tilt with the two sensors it has. The (simplified) intuition behind how this works is that the accelerometer gives a very good long-term estimate on tilt, but is rather poor for any single measurement, whereas the gyroscope is very effective for short-term measurements, but is inaccurate for the long-term.
The algorithm it uses to estimate tilt is essentially a combination of an accelerometer with a software "low pass filter" and a gyroscope with a software "high-pass filter. " The theory is as follows: in the long run an accelerometer can read the component of gravity acting on it.
When the device is completely horizontal, there is no gravity acting on the axis of measurement because gravity is therefore orthogonal to the Tipper. When straight up, the component of gravity is a full 9. 8 m/s. A software low pass filter is used to partially filter out the "noise" caused by the sensor reading the forward and backward acceleration of the Tipper and misinterpreting it as gravity.
There is a high-pass filter on the gyroscope because it is prone to integration drift. The gyroscope is not a tilt sensor, it is a rate of tilt sensor. To get changes in tilt, the controller integrates the data coming from the gyroscope. Over time, small errors accumulate making the estimated position increasingly incorrect. To account for this drift, a software high pass filter biases recent data from the gyroscope. When weighted and then combined, they give a fairly accurate estimate on the Tipper`s tilt. With the current system state (the tilt) now known, and the desired state a constant (upright the Tipper at all times), the controller can now command the motor speed controllers. The speed controllers are variable, which means the controller must choose a desired velocity for the motors and send that request to the speed controllers.
A PID (proportional, integral, derivative) control loop is used to pick the correct motor velocity in order to close the difference between the desired and current system state. The scale factors used in this control loop are very sensitive to changes. It took a great deal of time to fine tune the control loop to effectively stabilize the physical system.
The Tipper uses a custom dual H-bridge motor controller to regulate voltage to the two drive motors. Since voltage sets speed on a DC motor, these are effectively speed controllers. The H-bridge uses mosfets to switch current on and off the motors at a v