Example

This examples builds on the Oncilla API Level 0, which is the lowest Oncilla interface level. The examples was written for the Oncilla Simulation, but should work exactly the same later on the real hardware platform.

Simple Sine Movement

To show basic movement using the Oncilla interface, we provide a simple example performing a sine-movement on the Oncilla joint in position control, to generate a simple walking movement.

The source code below shows the example implementation. To perform the simple movement the following basic steps are done:

1. The actual robot object is instantiated (line 26). This connected either to the simulation backend or the real hardware.
2. We then grab the Synchronizer so that in the case of Simulation we can control the actual stepping of the Simulator by our own (line 30).
3. From the robot we take the joints we awant to use for the movement, in this case the Oncilla joints L1 and L2 and give them meaningful names.
4. To perform the actual movement we generate the desired JointAngles and set them as new position in the joints (examplary for two joints in lines 51-53).
5. Finally after we set new commands, we perform one simulation step (line 68) to let the commands have effect and to get current sensor values

#include <rsc/misc/langutils.h>

#include <rci/dto/JointAngles.h>

#include "liboncilla/Oncilla.h"


using namespace std;
using namespace boost;

using namespace rci;
using namespace rci::oncilla;

double hip_position(double phase,double amplitude,double offset){
	return amplitude * std::cos(phase) + offset;
}

double knee_position(double phase, double phase_lag,double amplitude,double offset){
	return amplitude *((phase + phase_lag) > M_PI ? 1.0 : 0.0) + offset;
}

int main() {

	// Instantiate the actual robot object
	Oncilla oncilla;

	// Get the synchronizer, so that we can control the actual simulation
	// stepping from within our code
	OncillaSynchronizerPtr synchronizer = oncilla.getSynchronizer();

	// Get all the joints we are interested in - L1 and L2
	OncillaL1Ptr left_fore_hip = oncilla.getL1(LEFT_FORE);
	OncillaL2Ptr left_fore_knee = oncilla.getL2(LEFT_FORE);
	OncillaL1Ptr right_fore_hip = oncilla.getL1(RIGHT_FORE);
	OncillaL2Ptr right_fore_knee = oncilla.getL2(RIGHT_FORE);
	OncillaL1Ptr left_hind_hip = oncilla.getL1(LEFT_HIND);
	OncillaL2Ptr left_hind_knee = oncilla.getL2(LEFT_HIND);
	OncillaL1Ptr right_hind_hip = oncilla.getL1(RIGHT_HIND);
	OncillaL2Ptr right_hind_knee = oncilla.getL2(RIGHT_HIND);

	//sets some parameter for the sinewave
	double hip_amplitude(10),
	       fore_hip_offset(0),
	       hind_hip_offset(0),
	       fore_knee_amplitude(0.5),
	       fore_knee_offset(0),
	       hind_knee_amplitude(0),
	       hind_knee_offset(0),
	       fore_hip_knee_phase_lag(0),
	       hind_hip_knee_phase_lag(0),
	       frequency(0.5);
	// Now move the joints
	double time_s, phase, antiphase;


	time_s = 0;
	while (true) {
		// The time is our phase - TODO: Use virtual / simulated time
		time_s += synchronizer->lastProcessTimeStep();
		phase = std::fmod(time_s * frequency * 2 * M_PI, 2 * M_PI);

		antiphase = std::fmod(phase + M_PI , 2 * M_PI);

		left_fore_hip->setJointPosition(JointAngles::fromDeg(hip_position(phase,hip_amplitude,fore_hip_offset)));
		left_fore_knee->setJointPosition(JointAngles::fromRad(knee_position(phase,fore_hip_knee_phase_lag,fore_knee_amplitude,fore_knee_offset)));

		right_fore_hip->setJointPosition(JointAngles::fromDeg(hip_position(antiphase,hip_amplitude,fore_hip_offset)));
		right_fore_knee->setJointPosition(JointAngles::fromRad(knee_position(antiphase,fore_hip_knee_phase_lag,fore_knee_amplitude,fore_knee_offset)));

		left_fore_hip->setJointPosition(JointAngles::fromDeg(hip_position(antiphase,hip_amplitude,hind_hip_offset)));
		left_fore_knee->setJointPosition(JointAngles::fromRad(knee_position(antiphase,hind_hip_knee_phase_lag,hind_knee_amplitude,hind_knee_offset)));

		right_fore_hip->setJointPosition(JointAngles::fromDeg(hip_position(phase,hip_amplitude,hind_hip_offset)));
		right_fore_knee->setJointPosition(JointAngles::fromRad(knee_position(phase,hind_hip_knee_phase_lag,hind_knee_amplitude,hind_knee_offset)));


		// Now that we set the new angles, we do one processing step
		synchronizer->process();
	}

	return EXIT_SUCCESS;
}

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