Steer by wire system with dynamic braking and endstop cushioning for haptic feel

A haptic feedback mechanism for a steer by wire system in a vehicle having a hand-operable controller for guiding movement of the vehicle based on an input motion from a user, the haptic feedback mechanism comprising:

• a DC motor connected to the hand-operable controller and configured to provide a haptic feedback to the user;
• electronic circuitry configured to control operation of the DC motor, wherein the electronic circuitry includes a node;
• a voltage sensor coupled to the node and configured to generate a first signal indicative of a voltage at the node indicative of a current of the DC motor;
• at least one current sense resistor coupled to the DC motor and configured to generate a second signal indicative of a current in the DC motor;
• a sensor assembly operatively coupled to the DC motor and configured to generate a speed signal indicative of a rotational speed of the input motion;
• a motor control logic module operatively connected to:
• the electronic circuitry;
• the voltage sensor and configured to receive the first signal;
• the at least one current sense resistor and configured to receive the second signal;
• and the sensor assembly and configured to receive the speed signal,
• the motor control logic module being operative to:
• make a first determination if the voltage at the node is above a predetermined threshold based upon the first signal;
• make a second determination if the current of the DC motor is above a requested current by the motor control logic based upon the second signal;
• make a third determination if the rotational speed is too high based upon the speed signal;
• and change the DC motor into an overcurrent prevention mode based on at least one of the first, second and third determinations,
• wherein in the overcurrent prevention mode, the motor control logic module uses the electronic circuitry to control the DC motor for a predetermined time period in which electrical power, generated by the input motion, passes through the DC motor to dissipate while maintaining the haptic feedback for the user;
• and
• an endstop mechanism including a position sensor configured to detect an angular position of the hand-operable controller, wherein the motor control logic module uses the electronic circuitry to increase the feedback torque within a predetermined range of an end of travel of the DC motor or hand-operable controller.