摘要:
A digital control for a multiaxis robot includes position, velocity and torque controls that drive a motor voltage control loop. Pulse width modulated control signals operate power switches in a power bridge to control the current to each robot joint motor. A single resistor is connected in the bridge circuit to supply motor current feedback needed for control loop operation.
摘要:
Circuitry is provided for applying a pulse width modulation (PWM) scheme to a brushless DC motor that operates as a robot axis drive. A pulse width modulation (PWM) scheme provides for digital implementation of robot control commands. For this purpose, it provides time stabilized current sampling synchronized to the sampling frequency of the position and velocity loops in the robot control. The brushless drive application circuitry provides for application of the PWM control outputs to commutate the motor energization from winding pair to winding pair.
摘要:
A digital robot control is provided with cascaded position/velocity and torque control loops with microprocessor servo controllers in each. The servo controller includes two microprocessors that operate as a servo engine in providing motion control for six robot axes. One microprocessor is structured to perform data processing and coordination tasks. The other one performs calculation tasks and operates as a slave processor to the first.
摘要:
A sampled data servo positioning system employs an actuator to move a member between a current and a target position. Incremental position feedback is provided only at sampling times. The system employs a model responsive to a velocity related input signal to produce a continually available model incremental position signal. Phase comparing means indicates phase differences between the model and sampled position signals at the sampling times.The system has two operational configurations in the first of which a source of saturation control signals is connected to the actuator to cause maximum acceleration or deceleration thereof. In this first configuration, the model is forced to track the actuator motion by means of feedforward plus feedback control. The feedforward signal represents actuator performance while the feedback signal is the position signal phase difference. In the second operational configuration, a velocity profile signal is applied to the model and the actuator is forced to track the model by means of feedforward plus feedback control. The feedback signal is again the position signal phase difference but the feedforward signal is a predetermined signal representing the desired actuator current to execute the velocity profile. The sampled data servo positioning system may be the access motion control system of a sector servo disk file.
摘要:
A computer assisted radiation therapy machine is disclosed. The machine includes a rotatable gantry having a radiation source portion and a beam stopping portion. The gantry is rotatable about a patient treatment couch which is rectilinearly translatable in three orthogonal directions as well as being rotatable about the vertical axis. Geometric and dose parameters defining a prescribed treatment plan of radiation are stored in the memory of the computer. Positional signals are derived from the various movable controls and parts of the radiation machine. The prescribed treatment parameters are compared with the actual positionings of the elements and controls of the machine to derive an interlock output when at least one of said actual parameters differs from the respective prescribed parameter. The interlock output is employed to inhibit application of radiation to the patient until the mistake is rectified.
摘要:
Example methods and apparatus to adjust control loop timing in a process control system are disclosed. A disclosed example method includes receiving a first input signal generated via a first process control device within a process control system, determining within the process control system if the first input signal is received during a first scheduled time period of a control loop, and adjusting within the process control system a timing of a subsequent input signal received from the first process control device to cause the subsequent input signal to be received during a subsequent scheduled time period of the control loop, wherein the timing of the subsequent input signal is based on at least when the first input signal was received.
摘要:
A digital compensator controls a servomechanism, such as the focus servo of an optical disk drive. The compensator waits one full sample period before applying the correction that was calculated for the proceeding sample. The compensator does not use the present input sample in its calculation of the present output sample. The method for operating the digital compensator comprises the steps of receiving a first input sample at time t.sub.1, receiving a second input sample at time t.sub.2, and computing a first output in response to the first input sample at time t.sub.2. The method does not require a present input sample to calculate a present output.
摘要:
An acceleration and deceleration method with steps that calculate transferring distance, average transferring speed in the x-direction and y-direction, intermediate destination position at every sampling time and the number of sampling times based on final destination position, initial current position and rectilinearly transferring speed; a step of determining initial position; and steps which calculate position pattern and destination position with linear equations, detect intermediate current position with linear equations, sequentially calculate position deviation and transferring speed per sampling time, so that the next step outputs a driving signal for a servo motor. Therefore, an object is transferred in exponential acceleration and deceleration according to linear equations describing rectilinearly transfer speed, and transferring distance in x-direction and y-direction.
摘要:
A pulse width moduation (PWM) scheme provides for digital implementation of robot control commands. For this purpose, it provides time stabilized current sampling synchronized to the sampling frequency of the position and velocity loops in the robot control. The PWM scheme enables accurate motor current measurement through usage of a single current sense resistor independent of the number of legs in a power amplifier configuration. This scheme permits commercially available, low cost, power blocks to be used for implementation of robot control system power amplifiers.The PWM scheme is cost effectively implemented in a semi-custom large scale integrated (LSI) circuit which provides the digital interface between a torque loop microprocessor and the drive circuitry for the power handling devices used to apply voltage to the robot axis actuator. Interface and control for three axes is provided by a single LSI device.
摘要:
A digital control is provided for a robot having a plurality of arm joints. The control includes an electric motor for driving each of the robot arm joints and a power amplifier supplies drive current to each motor.Each joint motor has feedback control loop means including at least digital position, velocity and torque control loops operable at a predetermined sampling rate to control the associated power amplifier. Digital motor position, velocity and drive current feedback signals are generated for the control loop means for all of the robot axes.Paired system microprocessors or paired position/velocity microprocessors generate position commands for the feedback control loop means in accordance with predefined moves set forth in a robot program. A planning program generates a time profile including acceleration, slew and deceleration time segments for each commanded robot program move.A trajectory program generates position commands for each of the feedback control loop means in accordance with a curved path trajectory and in accordance with the time profile applicable to the current move segment.The trajectory program employs stored third order polynomial equations and arc equations each having predetermined variable parameters operative to particularize that equation to a commanded curved path segment. The trajectory program responds to parameters specified by the robot program and implements the stored equations corresponding to the specified parameters to generate the position commands and define a tool tip trajectory corresponding to the curved path defined by the robot program.