Redundant accelerometer sensor system for absolute movement and orientation determination of a robotic arm

A robot comprising a robotic arm extending between a base end and a tool end and comprising a base at the base end and a plurality of joints including a first joint, a second joint, a third joint, a fourth joint, a fifth joint, and a sixth joint, the plurality of joints connecting the base and the tool end, the first joint being positioned between the base and the second joint, the second joint being positioned between the first joint and the third joint, the fourth joint being positioned between the third joint and the fifth joint, the fifth joint being positioned between the fourth joint and the sixth joint,

• the robotic arm comprising a plurality of motors including a first motor, a second motor and a third motor, the plurality of motors cause movement of the robotic arm with respect to a plurality of axes, the first motor causes movement of the first joint with respect to a first axis, the second motor causes movement of the second joint with respect to a second axis, and the third motor causes movement of the third joint with respect to a third axis,
• the base being a rigid part of the robot and comprising a plurality of accelerometers including a first accelerometer and a second accelerometer, the first accelerometer generating a first accelerometer signal indicative of acceleration sensed by the first accelerometer and the second accelerometer generating a second accelerometer signal indicative of acceleration sensed by the second accelerometer,
• the robot further comprising one or more processing units including a first processing unit and optionally a second processing unit, wherein the first processing unit receives the first accelerometer signal, and wherein the first processing unit determines orientation relative to gravity of the base based on the first accelerometer signal, and wherein the one or more processing units receives the second accelerometer signal and determines orientation relative to gravity of the base based on the second accelerometer signal,
• wherein the one or more processing units compares the determined orientation relative to gravity of the base based on the first accelerometer signal with the determined orientation relative to gravity of the base based on the second accelerometer signal, and
• in accordance with the comparison revealing that the determined orientations relative to gravity of the base differ by more than a differing threshold, the one or more processing units effectuate one or more safety functions of the robot, and
• in accordance with the comparison revealing that the determined orientations relative to gravity of the base does not differ by more than the differing threshold, the one or more processing units determines one or more operational parameters for the plurality of motors based on the determined orientation relative to gravity of the base.

A control unit for a robot comprising a robotic arm extending between a base end and a tool end and comprising a plurality of joints including a first joint, a second joint, a third joint, a fourth joint, a fifth joint, and a sixth joint, the control unit being adapted to be arranged at the base end of the robotic arm to form part of a rigid base of the robotic arm,

• the control unit comprising a plurality of accelerometers including a first accelerometer and a second accelerometer, the first accelerometer generates a first accelerometer signal indicative of acceleration sensed by the first accelerometer and the second accelerometer generates a second accelerometer signal indicative of acceleration sensed by the second accelerometer,
• the control unit further comprising one or more processing units including a first processing unit receiving the first accelerometer signal, and wherein the first processing unit determines orientation relative to gravity of the base of the robotic arm based on the first accelerometer signal, and wherein the one or more processing units receives the second accelerometer signal and determines orientation relative to gravity of the base based on the second accelerometer signal,
• wherein the one or more processing units compares the determined orientation relative to gravity of the base based on the first accelerometer signal with the determined orientation relative to gravity of the base based on the second accelerometer signal, and
• in accordance with the comparison revealing that the determined orientations relative to gravity of the base differ by more than a differing threshold, the one or more processing units effectuate one or more safety functions of the robot, and
• in accordance with the comparison revealing that the determined orientations relative to gravity of the base does not differ by more than the differing threshold, the one or more processing units determines one or more operational parameters for the plurality of motors based on the determined orientation relative to gravity of the base.