Servomotor control systems and methods

A radio controlled (RC) vehicle comprising:

• a servomotor comprising a servomotor shaft;
• a servomotor controller configured to generate one or more control signals for controlling the servomotor, wherein at least one of the control signals is a power control signal based at least in part on:
• (i) a rotation speed of the servomotor based at least in part on a back electromotive force measured at the servomotor, and (ii) a rotational direction of the servomotor;
• and
• wherein the one or more control signals comprise one or more directional control signals, and wherein the RC vehicle further comprises:
• an H-bridge circuit comprising four H-bridge terminals configurable to at least four states in response to the one or more directional control signals generated the servomotor controller;
• and
• a voltage divider configured to measure a voltage corresponding to a back electromotive force (EMF) generated by the rotation of the servomotor;
• wherein the first state enables current to flow across the servomotor from a first H-bridge terminal to a third H-bridge terminal to rotate the servomotor in a first direction;
• wherein the second state enables current to flow across the servomotor from a second H-bridge terminal to a fourth H-bridge terminal to rotate the servomotor in a second direction;
• wherein the third state creates a short across the first and second H-bridge terminals to cause the servomotor to brake;
• and
• wherein the fourth state creates a short across the third and fourth H-bridge terminals to cause the servomotor to brake.

A system comprising:

• a servomotor comprising a servomotor shaft;
• and
• control circuitry configured to generate one or more control signals for controlling the servomotor and a rotational position of the servomotor shaft, wherein the one or more control signals are based at least in part on:
• (i) servomotor braking caused by shorting two terminals of an H-bridge circuit configured to control a rotational speed and a rotational direction of the servomotor;
• (ii) a servomotor rotational speed based at least in part on a back electromotive force measured at the servomotor, and (iii) a servomotor rotational direction;
• wherein at least one control signal includes a power control signal determined according to the equation:
• power(t)=P(t)−V(t)+I(t);
• wherein P(t)=KP(error(t)), wherein KP is a proportional gain factor, wherein error(t)=θ*(t)−θ(t), wherein θ*(t) is the desired rotational position of the servomotor shaft, and wherein θ(t) is the measured rotational position of the servomotor shaft;
• wherein V(t)=KV×direction(t)×speed(t), wherein KV is a velocity gain factor, wherein direction(t) is the direction of the servomotor, and wherein speed(t) is the speed of the servomotor;
• and
• wherein I(t)=KI×∫(error(t))dt, wherein KI is an integral gain factor, and wherein ∫(error(t))dt corresponds an integral of error(t).

A method of controlling a servomotor comprising a servomotor shaft, the method comprising:

• determining a present rotational direction of the servomotor;
• determining a present rotational speed of the servomotor based at least in part on a back electromotive force measured at the servomotor;
• determining a present rotational velocity of the servomotor based at least in part on the determined rotational speed and determined rotational direction;
• generating at least one power control signal for controlling an amount of current applied to the servomotor based at least in part on the determined rotational velocity;
• and
• applying at least one servomotor control signal to the servomotor based at least in part on the at least one power control signal;
• wherein the rotational direction of the servomotor is based at least in part on an input received from a radio-controlled (RC) vehicle controller associated with an RC vehicle;
• calculating a positional error based on the difference between an actual rotational position of the servomotor shaft and a desired rotational position of the servomotor shaft;
• calculating an integral of the servomotor positional error over time;
• and
• wherein the at least one power control signal is based at least in part on the rotational velocity, the calculated positional error, and the calculated integral of the positional error.