An object of the present invention is to prevent unnecessary driving stop of a stepping motor. A robot arm section includes a robot arm, a stepping motor 31a, a motor driver 31b, an encoder 31c and a step-out detection section 31e. The robot arm has a joint J1. The stepping motor generates power for operating the joint. The motor driver drives the stepping motor according to a target angle. The encoder outputs an encoder pulse every time a drive shaft of the stepping motor rotates by a predetermined angle. The step-out detection section detects a step-out of the stepping motor based on the target angle and a current angle of the stepping motor that is identified based on the encoder pulse. When the stepping motor does not recover from the step-out before a predetermined grace time elapses from a time at which the step-out is detected, the motor driver stops driving the stepping motor at the time point at which the grace time elapses.

A multi-bar actuation assembly for use in installing a vehicle door to a vehicle includes a drive comprising a piston arm and a casing that movably receives the piston arm, a multi-bar linkage that includes a base support structure, a first bar link pivotally connected to the base support structure, a second bar link pivotally connected to the drive and the base support structure, and a toggle link that connects the first bar link and the second bar link, and a suction end effector pivotally connected to the toggle link at an end effector pivot that engages a window of the vehicle door. The drive extends and contracts the piston arm thereby moving the end effector pivot along a door arc about a door pivot axis with the suction end effector engaged with the window of the vehicle door.

A joint module has a base, a motion mechanism, a linear driving mechanism, a driving motor assembly, and a transmission. The motion mechanism, the linear driving mechanism, and the driving motor assembly are disposed on the base. The transmission is disposed between the linear driving mechanism and the driving motor assembly. A first transmitting assembly and a second transmitting assembly of the motion mechanism are disposed on the base in parallel. A first linear driving assembly and a second linear driving assembly of the linear driving mechanism are non-coaxial and are disposed on the base in parallel. A first wheel transmitting assembly of the transmission is connected to the driving motor assembly and the first linear driving assembly. A second wheel transmitting assembly of the transmission is connected to the driving motor assembly and the second linear driving assembly.

A motor control apparatus that controls a stepping motor includes a calculation unit configured to determine a time with respect to a distance based on a theoretical formula expressing a parameter in an acceleration period or deceleration period of the stepping motor. The calculation unit includes a first calculation unit and a second calculation unit. The first calculation unit is configured to apply an iterative root-finding procedure to a distance which is a function of a time included in the theoretical formula to determine the time with respect to the distance of the n-th step expressed using a reciprocal of a derivative of the function. The second calculation unit is configured to apply the iterative root-finding procedure to the reciprocal of the derivative to determine the reciprocal of the derivative at a time when the first calculation unit determines the time with respect to the distance of the n-th step.

A multi-bar actuation assembly for use in installing a vehicle door to a vehicle includes a drive comprising a piston arm and a casing that movably receives the piston arm, a multi-bar linkage that includes a base support structure, a first bar link pivotally connected to the base support structure, a second bar link pivotally connected to the drive and the base support structure, and a toggle link that connects the first bar link and the second bar link, and a suction end effector pivotally connected to the toggle link at an end effector pivot that engages a window of the vehicle door. The drive extends and contracts the piston arm thereby moving the end effector pivot along a door arc about a door pivot axis with the suction end effector engaged with the window of the vehicle door.

A joint module has a base, a motion mechanism, a linear driving mechanism, a driving motor assembly, and a transmission. The motion mechanism, the linear driving mechanism, and the driving motor assembly are disposed on the base. The transmission is disposed between the linear driving mechanism and the driving motor assembly. A first transmitting assembly and a second transmitting assembly of the motion mechanism are disposed on the base in parallel. A first linear driving assembly and a second linear driving assembly of the linear driving mechanism are non-coaxial and are disposed on the base in parallel. A first wheel transmitting assembly of the transmission is connected to the driving motor assembly and the first linear driving assembly. A second wheel transmitting assembly of the transmission is connected to the driving motor assembly and the second linear driving assembly.

An actuator has a linear driving mechanism, an output member, and an elastic member. The linear driving mechanism has a stepping motor, a thread rod assembly, and a linearly moveable member. The threaded rod assembly is connected with the stepping motor. The linearly moveable member is located at a side of the stepping motor and is connected with and driven by the thread rod assembly to reciprocatively move along a power input axis. The output member is disposed on a side of the linearly moveable member and has a capability of linearly moving along a power output axis that is co-axial with the power input axis. The elastic member is connected between the linearly moveable member and the output member to provide an elastic force along the power input axis.

A motor control apparatus that controls a stepping motor includes a calculation unit configured to determine a time with respect to a distance based on a theoretical formula expressing a parameter in an acceleration period or deceleration period of the stepping motor. The calculation unit includes a first calculation unit and a second calculation unit. The first calculation unit is configured to apply an iterative root-finding procedure to a distance which is a function of a time included in the theoretical formula to determine the time with respect to the distance of the n-th step expressed using a reciprocal of a derivative of the function. The second calculation unit is configured to apply the iterative root-finding procedure to the reciprocal of the derivative to determine the reciprocal of the derivative at a time when the first calculation unit determines the time with respect to the distance of the n-th step.

An object of the present invention is to prevent unnecessary driving stop of a stepping motor. A robot arm section includes a robot arm, a stepping motor 31a, a motor driver 31b, an encoder 31c and a step-out detection section 31e. The robot arm has a joint J1. The stepping motor generates power for operating the joint. The motor driver drives the stepping motor according to a target angle. The encoder outputs an encoder pulse every time a drive shaft of the stepping motor rotates by a predetermined angle. The step-out detection section detects a step-out of the stepping motor based on the target angle and a current angle of the stepping motor that is identified based on the encoder pulse. When the stepping motor does not recover from the step-out before a predetermined grace time elapses from a time at which the step-out is detected, the motor driver stops driving the stepping motor at the time point at which the grace time elapses.

Based on the premise that a step-out will occur in a stepping motor, this invention provides a suitable countermeasure for when a step-out occurs. A robot device includes: a robot arm mechanism having a joint; a stepping motor that generates motive power that actuates the joint; a motor driver that drives the stepping motor; a trajectory calculating section that calculates a trajectory along which an attention point of the robot arm mechanism moves from a current position to a final target position; a command value outputting section that outputs a command value in accordance with the trajectory calculated by the trajectory calculating section to the motor driver; and a step-out detecting section that detects a step-out of the stepping motor. The robot device also includes a system control section. When a step-out is detected, the system control section controls the trajectory calculating section and the command value outputting section so as to recalculate a trajectory to the final target position from a position of the attention point that is shifted due to the step-out, and to move the attention point in accordance with the recalculated trajectory.