# Joint control API¶

NAOqi Motion - Overview | API | Tutorial

## Method list¶

class ALMotionProxy
void ALMotionProxy::angleInterpolation(const AL::ALValue& names, const AL::ALValue& angleLists, const AL::ALValue& timeLists, const bool& isAbsolute)

Interpolates one or multiple joints to a target angle or along timed trajectories. This is a blocking call.

Parameters: names – Name or names of joints, chains, “Body”, “JointActuators”, “Joints” or “Actuators”. angleLists – An angle, list of angles or list of list of angles in radians timeLists – A time, list of times or list of list of times in seconds isAbsolute – If true, the movement is described in absolute angles, else the angles are relative to the current angle.

almotion_angleinterpolation.cpp

```#include <iostream>
#include <alproxies/almotionproxy.h>
#include <qi/os.hpp>

int main(int argc, char **argv)
{
std::string robotIp = "127.0.0.1";

if (argc < 2) {
std::cerr << "Usage: almotion_angleinterpolation robotIp "
<< "(optional default \"127.0.0.1\")."<< std::endl;
}
else {
robotIp = argv[1];
}

AL::ALMotionProxy motion(robotIp);

// Example showing a single target angle for one joint
AL::ALValue angleLists = 1.0f;
AL::ALValue timeLists  = 1.0f;
bool isAbsolute        = true;
std::cout << "Step 1: single target angle for one joint" << std::endl;
motion.angleInterpolation(names, angleLists, timeLists, isAbsolute);

qi::os::sleep(1.0f);

// Example showing a single trajectory for one joint
// Interpolate the head yaw to 1.0 radian and back to zero in 2.0 seconds
angleLists.clear();
angleLists = AL::ALValue::array(1.0f, 0.0f);
timeLists.clear();
timeLists  = AL::ALValue::array(1.0f, 2.0f);
isAbsolute = true;
std::cout << "Step 2: single trajectory for one joint" << std::endl;
motion.angleInterpolation(names, angleLists, timeLists, isAbsolute);

qi::os::sleep(1.0f);

// Example showing multiple trajectories
// Interpolate the HeadYaw to 1.0 radian and back to zero in 2.0 seconds
// while interpolating HeadPitch up and down over a longer period.
// Each joint can have lists of different lengths, but the number of
// angles and the number of times must be the same for each joint.
// Here, the second joint ("HeadPitch") has three angles, and
// three corresponding times.
angleLists.clear();
angleLists.arraySetSize(2);
angleLists[0] = AL::ALValue::array(1.0f, 0.0f);
angleLists[1] = AL::ALValue::array(-0.5f, 0.5f, 0.0f);

timeLists.clear();
timeLists.arraySetSize(2);
timeLists[0] = AL::ALValue::array(1.0f, 2.0f);
timeLists[1] = AL::ALValue::array(1.0f, 2.0f, 3.0f);

isAbsolute = true;
std::cout << "Step 3: multiple trajectories" << std::endl;
motion.angleInterpolation(names, angleLists, timeLists, isAbsolute);

return 0;
}
```

almotion_angleinterpolation.py

```# -*- encoding: UTF-8 -*-

import sys
import time
from naoqi import ALProxy
import almath

def main(robotIP):
PORT = 9559

try:
motionProxy = ALProxy("ALMotion", robotIP, PORT)
except Exception,e:
print "Could not create proxy to ALMotion"
print "Error was: ",e
sys.exit(1)

# Example showing a single target angle for one joint
timeLists  = 1.0
isAbsolute = True
motionProxy.angleInterpolation(names, angleLists, timeLists, isAbsolute)

time.sleep(1.0)

# Example showing a single trajectory for one joint
# Interpolate the head yaw to 1.0 radian and back to zero in 2.0 seconds
#              2 angles
#              2 times
timeLists  = [1.0, 2.0]
isAbsolute = True
motionProxy.angleInterpolation(names, angleLists, timeLists, isAbsolute)

time.sleep(1.0)

# Example showing multiple trajectories
timeLists  = [1.0, 1.2]
isAbsolute = True
motionProxy.angleInterpolation(names, angleLists, timeLists, isAbsolute)

# Example showing multiple trajectories
# Interpolate the head yaw to 1.0 radian and back to zero in 2.0 seconds
# while interpolating HeadPitch up and down over a longer period.
# Each joint can have lists of different lengths, but the number of
# angles and the number of times must be the same for each joint.
# Here, the second joint ("HeadPitch") has three angles, and
# three corresponding times.
timeLists   = [[1.0, 2.0], [ 1.0, 2.0, 3.0]]
isAbsolute  = True
motionProxy.angleInterpolation(names, angleLists, timeLists, isAbsolute)

if __name__ == "__main__":
robotIp = "127.0.0.1"

if len(sys.argv) <= 1:
print "Usage python almotion_angleinterpolation.py robotIP (optional default: 127.0.0.1)"
else:
robotIp = sys.argv[1]

main(robotIp)
```
void ALMotionProxy::angleInterpolationWithSpeed(const AL::ALValue& names, const AL::ALValue& targetAngles, const float& maxSpeedFraction)

Interpolates one or multiple joints to a target angle, using a fraction of max speed. Only one target angle is allowed for each joint. This is a blocking call.

Parameters: names – Name or names of joints, chains, “Body”, “JointActuators”, “Joints” or “Actuators”. targetAngles – An angle, or list of angles in radians maxSpeedFraction – A fraction.

almotion_angleinterpolationwithspeed.cpp

```#include <iostream>
#include <alproxies/almotionproxy.h>
#include <qi/os.hpp>

int main(int argc, char **argv)
{
std::string robotIp = "127.0.0.1";

if (argc < 2) {
std::cerr << "Usage: almotion_angleinterpolationwithspeed robotIp "
<< "(optional default \"127.0.0.1\")."<< std::endl;
}
else {
robotIp = argv[1];
}

AL::ALMotionProxy motion(robotIp);

// Example showing a single target for one joint
AL::ALValue targetAngles = 1.0f;
float maxSpeedFraction   = 0.2f; // Using 20% of maximum joint speed
std::cout << "Step 1: single target for one joint." << std::endl;
motion.angleInterpolationWithSpeed(names, targetAngles, maxSpeedFraction);

qi::os::sleep(1.0f);

// Example showing multiple joints
// Instead of listing each joint, you can use a chain name, which will
// be expanded to contain all the joints in the chain. In this case,
// We still need to specify the correct number of target angles
targetAngles = AL::ALValue::array(0.5f, 0.25f);
maxSpeedFraction  = 0.2f; // Using 20% of maximum joint speed
std::cout << "Step 2: multiple joints." << std::endl;
motion.angleInterpolationWithSpeed(names, targetAngles, maxSpeedFraction);

return 0;
}
```

almotion_angleinterpolationwithspeed.py

```# -*- encoding: UTF-8 -*-

import sys
import time
from naoqi import ALProxy

def main(robotIP):
PORT = 9559

try:
motionProxy = ALProxy("ALMotion", robotIP, PORT)
except Exception,e:
print "Could not create proxy to ALMotion"
print "Error was: ",e
sys.exit(1)

# Example showing multiple trajectories
# Interpolate the head yaw to 1.0 radian and back to zero in 2.0 seconds
# while interpolating HeadPitch up and down over a longer period.
# Each joint can have lists of different lengths, but the number of
# angles and the number of times must be the same for each joint.
# Here, the second joint ("HeadPitch") has three angles, and
# three corresponding times.
angleLists  = [[1.0, 0.0], [-0.5, 0.5, 0.0]]
timeLists   = [[1.0, 2.0], [ 1.0, 2.0, 3.0]]
isAbsolute  = True
motionProxy.angleInterpolation(names, angleLists, timeLists, isAbsolute)

time.sleep(1.0)

# Example showing a single target for one joint
targetAngles      = 1.0
maxSpeedFraction  = 0.2 # Using 20% of maximum joint speed
motionProxy.angleInterpolationWithSpeed(names, targetAngles, maxSpeedFraction)

time.sleep(1.0)

# Example showing multiple joints
# Instead of listing each joint, you can use a chain name, which will
# be expanded to contain all the joints in the chain. In this case,
# We still need to specify the correct number of target angles
targetAngles     = [0.5, 0.25]
maxSpeedFraction = 0.2 # Using 20% of maximum joint speed
motionProxy.angleInterpolationWithSpeed(names, targetAngles, maxSpeedFraction)

motionProxy.setStiffnesses("Body", 1.0)

# Example showing body zero position
# Instead of listing each joint, you can use a the name "Body"
names  = "Body"
# We still need to specify the correct number of target angles, so
# we need to find the number of joints that this Nao has.
# Here we are using the getBodyNames method, which tells us all
# the names of the joints in the alias "Body".
# We could have used this list for the "names" parameter.
numJoints = len(motionProxy.getBodyNames("Body"))
# Make a list of the correct length. All angles are zero.
targetAngles  = [0.0]*numJoints
# Using 10% of maximum joint speed
maxSpeedFraction  = 0.1
motionProxy.angleInterpolationWithSpeed(names, targetAngles, maxSpeedFraction)

if __name__ == "__main__":
robotIp = "127.0.0.1"

if len(sys.argv) <= 1:
print "Usage python almotion_angleinterpolationwithspeed.py robotIP (optional default: 127.0.0.1)"
else:
robotIp = sys.argv[1]

main(robotIp)
```
void ALMotionProxy::angleInterpolationBezier(const std::vector<std::string>& jointNames, const AL::ALValue& times, const AL::ALValue& controlPoints)

Interpolates a sequence of timed angles for several motors using Bezier control points. This is a blocking call.

Parameters: jointNames – A vector of joint names times – An ragged ALValue matrix of floats. Each line corresponding to a motor, and column element to a control point. controlPoints – An ALValue array of arrays each containing [float angle, Handle1, Handle2], where Handle is [int InterpolationType, float dAngle, float dTime] describing the handle offsets relative to the angle and time of the point. The first Bezier param describes the handle that controls the curve preceding the point, the second describes the curve following the point.
void ALMotionProxy::setAngles(const AL::ALValue& names, const AL::ALValue& angles, const float& fractionMaxSpeed)

Sets angles. This is a non-blocking call.

Parameters: names – The name or names of joints, chains, “Body”, “JointActuators”, “Joints” or “Actuators”. angles – One or more angles in radians fractionMaxSpeed – The fraction of maximum speed to use

almotion_setangles.cpp

```#include <iostream>
#include <alproxies/almotionproxy.h>
#include <qi/os.hpp>

int main(int argc, char **argv)
{
std::string robotIp = "127.0.0.1";

if (argc < 2) {
std::cerr << "Usage: almotion_setangles robotIp "
<< "(optional default \"127.0.0.1\")."<< std::endl;
}
else {
robotIp = argv[1];
}

AL::ALMotionProxy motion(robotIp);

// Example showing how to set angles, using a fraction of max speed
AL::ALValue angles      = AL::ALValue::array(0.3f, -0.3f);
float fractionMaxSpeed  = 0.1f;
motion.setStiffnesses(names, AL::ALValue::array(1.0f, 1.0f));
qi::os::sleep(1.0f);
motion.setAngles(names, angles, fractionMaxSpeed);
qi::os::sleep(1.0f);
motion.setStiffnesses(names, AL::ALValue::array(0.0f, 0.0f));

return 0;
}
```

almotion_setangles.py

```# -*- encoding: UTF-8 -*-

import sys
from naoqi import ALProxy
import time

def main(robotIP):
PORT = 9559

try:
motionProxy = ALProxy("ALMotion", robotIP, PORT)
except Exception,e:
print "Could not create proxy to ALMotion"
print "Error was: ",e
sys.exit(1)

# Example showing how to set angles, using a fraction of max speed
angles  = [0.2, -0.2]
fractionMaxSpeed  = 0.2
motionProxy.setAngles(names, angles, fractionMaxSpeed)

time.sleep(3.0)

if __name__ == "__main__":
robotIp = "127.0.0.1"

if len(sys.argv) <= 1:
print "Usage python almotion_setangles.py robotIP (optional default: 127.0.0.1)"
else:
robotIp = sys.argv[1]

main(robotIp)
```
void ALMotionProxy::changeAngles(const AL::ALValue& names, const AL::ALValue& changes, const float& fractionMaxSpeed)

Changes Angles. This is a non-blocking call.

Parameters: names – The name or names of joints, chains, “Body”, “JointActuators”, “Joints” or “Actuators”. changes – One or more changes in radians fractionMaxSpeed – The fraction of maximum speed to use

almotion_changeangles.cpp

```#include <iostream>
#include <alproxies/almotionproxy.h>
#include <qi/os.hpp>

int main(int argc, char **argv)
{
std::string robotIp = "127.0.0.1";

if (argc < 2) {
std::cerr << "Usage: almotion_changeangles robotIp "
<< "(optional default \"127.0.0.1\")."<< std::endl;
}
else {
robotIp = argv[1];
}

AL::ALMotionProxy motion(robotIp);

// Example showing a slow, relative move of "HeadYaw".
// Calling this multiple times will move the head further.
AL::ALValue changes    = 0.25f;
float fractionMaxSpeed = 0.05f;
motion.changeAngles(names, changes, fractionMaxSpeed);

qi::os::sleep(1.0f);

return 0;
}
```

almotion_changeangles.py

```# -*- encoding: UTF-8 -*-

import sys
import time
from naoqi import ALProxy

def main(robotIP):
PORT = 9559

try:
motionProxy = ALProxy("ALMotion", robotIP, PORT)
except Exception,e:
print "Could not create proxy to ALMotion"
print "Error was: ",e
sys.exit(1)

# Example showing a slow, relative move of "HeadYaw".
# Calling this multiple times will move the head further.
changes          = 0.5
fractionMaxSpeed = 0.05
motionProxy.changeAngles(names, changes, fractionMaxSpeed)

time.sleep(2.0)

if __name__ == "__main__":
robotIp = "127.0.0.1"

if len(sys.argv) <= 1:
print "Usage python almotion_changeangles.py robotIP (optional default: 127.0.0.1)"
else:
robotIp = sys.argv[1]

main(robotIp)
```
std::vector<float> ALMotionProxy::getAngles(const AL::ALValue& names, const bool& useSensors)

Gets the angles of the joints

Parameters: names – Names the joints, chains, “Body”, “JointActuators”, “Joints” or “Actuators”. useSensors – If true, sensor angles will be returned Joint angles in radians.

almotion_getangles.cpp

```#include <iostream>
#include <alproxies/almotionproxy.h>

int main(int argc, char **argv)
{
std::string robotIp = "127.0.0.1";

if (argc < 2) {
std::cerr << "Usage: almotion_getangles robotIp "
<< "(optional default \"127.0.0.1\")."<< std::endl;
}
else {
robotIp = argv[1];
}

AL::ALMotionProxy motion(robotIp);

// Example that finds the difference between the command and sensed angles.
std::string names = "Body";
bool useSensors   = false;
std::vector<float> commandAngles = motion.getAngles(names, useSensors);
std::cout << "Command angles: " << std::endl << commandAngles << std::endl;
useSensors = true;
std::vector<float> sensorAngles = motion.getAngles(names, useSensors);
std::cout << "Sensor angles: " << std::endl << sensorAngles << std::endl;

return 0;
}
```

almotion_getangles.py

```# -*- encoding: UTF-8 -*-

import sys
from naoqi import ALProxy

def main(robotIP):
PORT = 9559

try:
motionProxy = ALProxy("ALMotion", robotIP, PORT)
except Exception,e:
print "Could not create proxy to ALMotion"
print "Error was: ",e
sys.exit(1)

# Example that finds the difference between the command and sensed angles.
names         = "Body"
useSensors    = False
commandAngles = motionProxy.getAngles(names, useSensors)
print "Command angles:"
print str(commandAngles)
print ""

useSensors  = True
sensorAngles = motionProxy.getAngles(names, useSensors)
print "Sensor angles:"
print str(sensorAngles)
print ""

errors = []
for i in range(0, len(commandAngles)):
errors.append(commandAngles[i]-sensorAngles[i])
print "Errors"
print errors

if __name__ == "__main__":
robotIp = "127.0.0.1"

if len(sys.argv) <= 1:
print "Usage python almotion_getangles.py robotIP (optional default: 127.0.0.1)"
else:
robotIp = sys.argv[1]

main(robotIp)
```
void ALMotionProxy::closeHand(const std::string& handName)

Closes the hand, then cuts motor current to conserve energy. This is a blocking call.

Parameters: handName – The name of the hand. Could be: “RHand” or “LHand”

almotion_closehand.cpp

```#include <iostream>
#include <alproxies/almotionproxy.h>
#include <qi/os.hpp>

int main(int argc, char **argv)
{
std::string robotIp = "127.0.0.1";

if (argc < 2) {
std::cerr << "Usage: almotion_closehand robotIp "
<< "(optional default \"127.0.0.1\")."<< std::endl;
}
else {
robotIp = argv[1];
}

AL::ALMotionProxy motion(robotIp);

// Example showing how to close the right hand.
const std::string handName = "RHand";
motion.closeHand(handName);

return 0;
}
```

almotion_closehand.py

```# -*- encoding: UTF-8 -*-

import sys
from naoqi import ALProxy

def main(robotIP):
PORT = 9559

try:
motionProxy = ALProxy("ALMotion", robotIP, PORT)
except Exception,e:
print "Could not create proxy to ALMotion"
print "Error was: ",e
sys.exit(1)

# Example showing how to close the right hand.
handName  = 'RHand'
motionProxy.closeHand(handName)

if __name__ == "__main__":
robotIp = "127.0.0.1"

if len(sys.argv) <= 1:
print "Usage python almotion_closehand.py robotIP (optional default: 127.0.0.1)"
else:
robotIp = sys.argv[1]

main(robotIp)
```
void ALMotionProxy::openHand(const std::string& handName)

Opens the hand, then cuts motor current to conserve energy. This is a blocking call.

Parameters: handName – The name of the hand. Could be: “RHand or “LHand”

almotion_openhand.cpp

```#include <iostream>
#include <alproxies/almotionproxy.h>

int main(int argc, char **argv)
{
std::string robotIp = "127.0.0.1";

if (argc < 2) {
std::cerr << "Usage: almotion_openhand robotIp "
<< "(optional default \"127.0.0.1\")."<< std::endl;
}
else {
robotIp = argv[1];
}

AL::ALMotionProxy motion(robotIp);

// Example showing how to open the right hand.
std::string handName = "RHand";
motion.openHand(handName);

return 0;
}
```

almotion_openhand.py

```# -*- encoding: UTF-8 -*-

import sys
from naoqi import ALProxy

def main(robotIP):
PORT = 9559

try:
motionProxy = ALProxy("ALMotion", robotIP, PORT)
except Exception,e:
print "Could not create proxy to ALMotion"
print "Error was: ",e
sys.exit(1)

# Example showing how to open the left hand
motionProxy.openHand('LHand')

if __name__ == "__main__":
robotIp = "127.0.0.1"

if len(sys.argv) <= 1:
print "Usage python almotion_openhand.py robotIP (optional default: 127.0.0.1)"
else:
robotIp = sys.argv[1]

main(robotIp)
```