Module motion 

The C ABI for the motion helpers: chassis kinematics, an arm, odometry, waypoint guidance, the safety gate, and the conversions to servo, ESC, and encoder units.

These wrap the robotics half of pamoja_kit. The kinematic models, the arm, the waypoint follower, and the servo, ESC, and encoder scales hold only their parameters and never change, so each crosses by value as a small struct the caller fills in and passes to every call; the helper applies the same fallbacks the Rust constructor does, such as taking a length’s magnitude. The helpers that remember something between calls, the odometry, the e-stop, the watchdog, the limits, the safety gate, and the quadrature decoder, are opaque handles, each with its own _free. A constructor never returns null, and each method documents what it returns for a null handle.

Structs

PamojaAckermann

Car-like steering: one steered axle and a driven axle wheelbase apart.

PamojaBodyMotion

A planar body motion: a forward speed and a yaw rate.

PamojaDhParameters

One joint of a serial arm in the Denavit-Hartenberg convention.

PamojaDiffDrive

A differential drive: two wheels track apart.

PamojaEStop

An opaque handle to a latching emergency stop.

PamojaEsc

An electronic speed controller’s reverse, neutral, and forward pulse widths.

PamojaGuidance

The command toward a waypoint, with the geometry behind it.

PamojaJoints

A two-link arm’s joint angles, in radians.

PamojaLimits

An opaque handle to speed and acceleration limits, with the motion they last allowed.

PamojaMecanum

A mecanum base: four wheels wheelbase front to rear and track side to side.

PamojaOdometry

An opaque handle to a dead-reckoned pose.

PamojaPoint

A point in a plane.

PamojaPose

Where a robot is and which way it faces.

PamojaQuadrature

An opaque handle to a quadrature encoder decoder.

PamojaQuadratureScale

An encoder’s resolution and the radius of the wheel it turns with.

PamojaReach

The closest and farthest a two-link arm’s hand reaches from its shoulder.

PamojaSafetyGate

An opaque handle to the gate every motion command passes through: an e-stop, a watchdog, and limits.

PamojaServoMap

A hobby servo’s pulse range and travel.

PamojaSideSpeeds

The speeds of a two-sided drive’s left and right wheels or tracks.

PamojaSkidSteer

A skid-steer drive: tracks or wheels track apart that slip sideways to turn.

PamojaTransform

A 4x4 homogeneous transform, a rotation and a translation, stored row-major.

PamojaTwist

How fast a robot is asked to move.

PamojaTwoLinkArm

A planar two-link arm: a shoulder link l1 long and an elbow link l2 long.

PamojaWatchdog

An opaque handle to a deadman timer.

PamojaWaypointFollower

Steers toward a waypoint: the speeds and gains of a carrot-following guide.

PamojaWheelSpeeds

The four wheel speeds of a mecanum base.

Enums

PamojaElbow

Which way a two-link arm’s elbow bends.

Functions

pamoja_ackermann_curvature

Returns the path curvature of a steering angle, the reciprocal of the turn radius.

pamoja_ackermann_steering_angle

Returns the steering angle for a forward speed and a yaw rate.

pamoja_ackermann_turn_radius

Returns the turn radius of a steering angle.

pamoja_ackermann_yaw_rate

Returns the yaw rate a forward speed and a steering angle produce.

pamoja_dh_transform

Returns the transform one Denavit-Hartenberg joint makes.

pamoja_diff_drive_body_motion

Returns the body motion a differential drive makes from measured wheel speeds.

pamoja_diff_drive_wheel_speeds

Returns the wheel speeds a differential drive needs for a body motion.

pamoja_esc_bidirectional

Returns the common reversible ESC: 1000, 1500, and 2000 microseconds.

pamoja_esc_pulse

Returns the pulse width for a throttle.

pamoja_estop_engage^⚠

Engages an e-stop; it holds until reset.

pamoja_estop_free^⚠

Releases an e-stop handle.

pamoja_estop_gate^⚠

Passes a command through an e-stop.

pamoja_estop_is_engaged^⚠

Reports whether an e-stop is engaged.

pamoja_estop_new^⚠

Creates an e-stop that is not engaged.

pamoja_estop_reset^⚠

Clears an e-stop.

pamoja_forward_kinematics^⚠

Returns the transform from a serial arm’s base to its tool.

pamoja_limits_apply^⚠

Bounds a command in speed and acceleration.

pamoja_limits_free^⚠

Releases a limits handle.

pamoja_limits_new^⚠

Creates limits on speed and acceleration, starting from rest.

pamoja_limits_reset^⚠

Forgets the motion limits last allowed, so the next command eases up from rest.

pamoja_mecanum_body_motion

Returns the body twist a mecanum base makes from measured wheel speeds.

pamoja_mecanum_wheel_speeds

Returns the four wheel speeds a mecanum base needs for a body twist.

pamoja_obstacle_stop

Cuts forward and sideways motion when an obstacle is within the stopping distance.

pamoja_odometry_free^⚠

Releases an odometry handle.

pamoja_odometry_fuse_heading^⚠

Nudges an odometry estimate’s heading toward an absolute measurement.

pamoja_odometry_integrate^⚠

Integrates a body motion over a time step onto an odometry estimate.

pamoja_odometry_integrate_wheels^⚠

Integrates the distances two wheels rolled onto an odometry estimate.

pamoja_odometry_new^⚠

Creates an odometry estimate starting from a known pose.

pamoja_odometry_pose^⚠

Reads an odometry estimate’s pose.

pamoja_odometry_reset^⚠

Sets an odometry estimate to a known pose.

pamoja_quadrature_count^⚠

Reads a quadrature decoder’s signed count of steps.

pamoja_quadrature_free^⚠

Releases a quadrature decoder handle.

pamoja_quadrature_new^⚠

Creates a quadrature decoder seeded with the encoder’s current channel levels.

pamoja_quadrature_reset^⚠

Sets a quadrature decoder’s count back to 0, keeping the channel state it last read.

pamoja_quadrature_scale_distance

Returns the distance a wheel rolled for a step count.

pamoja_quadrature_scale_velocity

Returns a wheel’s speed from the steps counted over a time step.

pamoja_quadrature_update^⚠

Feeds a quadrature decoder the channel levels it reads now.

pamoja_safety_gate_command^⚠

Returns the command that is safe to drive for a desired one over a time step.

pamoja_safety_gate_engage_estop^⚠

Engages a safety gate’s latching e-stop.

pamoja_safety_gate_feed^⚠

Feeds a safety gate’s watchdog; call it whenever a fresh command arrives.

pamoja_safety_gate_free^⚠

Releases a safety gate handle.

pamoja_safety_gate_is_stopped^⚠

Reports whether a safety gate is forcing a stop.

pamoja_safety_gate_new^⚠

Creates a safety gate from limits and a watchdog timeout.

pamoja_safety_gate_reset_estop^⚠

Clears a safety gate’s e-stop.

pamoja_servo_map_angle

Returns the angle a servo pulse width sets.

pamoja_servo_map_pulse

Returns the pulse width that sets a servo to an angle.

pamoja_servo_map_standard

Returns the standard hobby servo: 1000 to 2000 microseconds over 180 degrees.

pamoja_skid_steer_body_motion

Returns the body motion a skid-steer drive makes from measured side speeds.

pamoja_skid_steer_wheel_speeds

Returns the side speeds a skid-steer drive needs for a body motion.

pamoja_transform_identity

Returns the identity transform: no rotation and no translation.

pamoja_transform_multiply

Returns the transform that applies second and then first, their product.

pamoja_two_link_arm_joints_for^⚠

Finds the joint angles that put a two-link arm’s hand at a point.

pamoja_two_link_arm_reach

Returns how close and how far a two-link arm reaches.

pamoja_two_link_arm_tip

Returns where a two-link arm’s hand is for its joint angles.

pamoja_watchdog_feed^⚠

Feeds a watchdog, restarting its silence timer.

pamoja_watchdog_free^⚠

Releases a watchdog handle.

pamoja_watchdog_is_expired^⚠

Reports whether a watchdog has expired.

pamoja_watchdog_new^⚠

Creates a watchdog that expires after timeout without being fed.

pamoja_watchdog_update^⚠

Advances a watchdog’s timer and reports whether it has expired.

pamoja_waypoint_follower_guide

Produces the command from a robot’s position and heading toward a target.