Servo

Hardware Interface

Defined in namespace hal

#include <libhal/servo.hpp>

class servo

Hardware abstraction for a closed loop position controlled rotational actuator.

Subclassed by hal::soft::rc_servo

Public Functions

inline result<position_t> position(hal::degrees p_position)

Set the position of the servo’s output shaft.

Position is the rotational position as a angle in degrees that the caller wants the shaft to rotate to. The allowed range of positions is defined by the servo itself. Many servos have intrinsic limits to their range.

Developers must choose servos that fit the range for their applications. Applications must clearly define the range that they require in order to perform correctly.

The velocity in which the servo shaft moves is not defined by this function but is either intrinsic to the servo or a configuration of the servo.

Parameters:

p_position – - the position to move the servo shaft in degrees.

Throws:

• std::errc::invalid_argument – - when position exceeds the range of the servo. When this error occurs, the guaranteed behavior is that the servo keeps its last set position.

• hal::servo::range_error – - when position exceeds the range of the servo. Provides details about the min and max range of the servo. When this error occurs, the guaranteed behavior is that the servo keeps its last set position.

Returns:

result<position_t> - success or failure

struct position_t

Feedback from setting the servo position.

This structure is currently empty as no feedback has been determined for now. This structure may be expanded in the future.

struct range_error

Error information indicating the range of the servo.

Public Members

hal::degrees min

Minimum range of the servo shaft in degrees.

hal::degrees max

Maximum range of the servo shaft in degrees.