Motion control of work vehicle

A work vehicle comprising:

• a boom assembly having an end effector;
• an actuator engaged to the boom assembly, wherein the actuator is adapted to position the boom assembly;
• an actuator sensor adapted to measure the displacement of the actuator;
• a flow control valve being in fluid communication with the actuator;
• a controller being in electrical communication with the flow control valve, the controller being adapted to actuate the flow control valve in response to an input signal, wherein the controller includes a motion control scheme that includes:
• a coordinate transformation module that converts a desired coordinate of the end effector of the boom assembly from Cartesian space to actuator space;
• a deflection compensation module that calculates a deflection error of the end effector due to bending of the boom assembly based on measurements from the actuator sensor;
• an axis control module that generates a control signal based on the desired coordinate, the deflection error and the measurements from the actuator sensor;
• and
• an input shaping module that shapes the control signal transmitted to the flow control valve to reduce vibration of the boom assembly.

A method of calibrating the damping ratio and the natural frequency of a boom assembly using a flow control valve, the method comprising:

• receiving pressure signals from pressure sensors regarding pressure in an actuator;
• recording high and low pressure values and times associated with those pressure values for a first cycle;
• recording high and low pressure values and times associated with those pressure values for a second cycle;
• and
• calculating natural frequency and damping ratio based on the pressure values and times associated with those pressure values for the first and second cycles.

A method for shaping a control signal for a control valve in fluid communication with an actuator for a flexible structure, the method comprising:

• generating a control signal based on a desired coordinate;
• shaping the control signal using a time-varying input shaping scheme, wherein the time-varying input shaping scheme:
• receives a measurement from a sensor;
• estimates a natural frequency and damping ratio of the flexible structure based on the measurement of the sensor;
• and
• shapes the control signal based on the measurement and the estimated natural frequency and damping ratio,
• transmitting the shaped control signal to the control valve.