[SP] Temperature of brake motor

[datahaki]

Background

• The brake of the gokart is operated by a linear motor ("linmot").
• When the shaft of the motor is in "home" position, no braking occurs and no energy is consumed.
• For maximum brake effect, the motor maintains the shaft at position ~42[mm]. In that state, the motor heats up significantly.
• The temperature of the motor should not exceed 110[degC].

Task description

• investigate the linmot heatup from log files of MPC operation. given a typical lap and use of brake, quantify the number of laps that can be driven until the max. temperature is reached.
• Create a transfer function model that approximates the motor heat curve depending on the input signal that is the brake position.
• Since the brake operation is required for a certain period of time during emergency stop, the task is to bound the permitted speed of the gokart depending on the current linmot temperature. Example: At a velocity of 6[m/s] requires 1.3[s] of brake action to come to a complete stop. During that time, the brake is estimated to heat up by X[degC]. Therefore, a motor temperature of 110-X[degC] is required prior to the emergency stop.

Visualization

Brake action and Linmot temperature during experiment