Some skillful drivers can drive and balance a four wheeled vehicle on two wheels. To verify that a control system can also drive a car in this fashion, a prototype using an RC (remote-controlled) car is equipped with a feedback control system (Arndt, 2011). In a simplified system model, the roll angle at which the car balances was calculated a priori and found to be 52.3°.

This value was used as the desired input. The desired input is compared with the actual roll angle and the difference is fed to a controller that feeds a servomotor indicating the desired wheel steering angle that controls the vehicle's roll angle on two wheels.

The car's actual roll angle is measured using a hinged linkage that rolls along the ground next to the vehicle and is connected to a potentiometer.

Draw a block diagram indicating the system functions. Draw blocks for the system controller, the steering servo, and the car dynamics.

Indicate in the diagram the following signals: the desired roll angle, the steering wheel angle, and the actual car roll angle.