By wire control of braking and acceleration

A method of providing an electrical braking function through an electrical motor in a surface maintenance vehicle to proximate the feel of a mechanical braking system, comprising the steps of:

• a. engaging a brake pedal to initiate braking function;
• b. sensing the position of the brake pedal and encoding the pedal position as an electronic signal;
• c. sensing the vehicle velocity;
• d. using said vehicle velocity and said signal, determining a desired machine deceleration rate to approximate the sensation of mechanical braking;
• e. generating a series of pulses of frequency greater than the response frequency of the motor;
• f. within each pulse defining the desired duty cycle to create an effective conductance;
• g. applying the effective conductance in parallel with the motor to cause machine deceleration by dynamic braking;
• and
• h. iteratively checking vehicle velocity and brake pedal position and correspondingly altering duty cycle to respond to demand for greater or lesser braking.

An electrically powered surface maintenance machine with dynamic braking capable of proximating mechanical braking response, comprising:

• a. an electric motor;
• b. a brake pedal having a position sensor;
• c. an encoder for converting the pedal position to an electrical pedal position signal;
• d. a machine velocity sensor;
• e. a braking rate controller capable of determining braking force tuned to approximate mechanical braking, in response to the electrical pedal position signal and the machine velocity;
• f. a converter to translate braking rate to an effective electrical load to be applied in parallel to the motor;
• g. an updater for iteratively checking the machine velocity and the pedal position and repeatedly adjusting the braking rate and thereby adjusting the effective electrical load applied in parallel to the motor;
• and
• wherein the effective electrical load is determined by a series of pulses of frequency greater than the response frequency of the motor.