Abstract:
A method and apparatus for incorporating fuzzy logic into a feedback controller is provided. An error signal and the derivative of feedback or error is provided to the fuzzy logic to develop a proportional and differential signal, the differential signal is subsequently integrated and added to the proportional signal to create a control output of the controller. The fuzzy rules of the fuzzy logic decrease the integral term under situations that might lead to "wind-up".
Abstract:
A reflex I/O card for an industrial controller receives enabling inputs from the executed control program and triggering inputs from an industrial process to provide outputs at a fixed delay in time or portion of a machine cycle after the inputs through dedicated hardware thus avoiding transmission delays and processing delays associated with the communication of information to a central processor and the execution of the control program.
Abstract:
A multi-tasking operating system for real-time control of industrial processes integrates ladder type programs and state-type programs by viewing each as a series of instructions with an implicit pointer list pointing to the next instruction. A fixed number of instructions of each program task are executed after which the effective pointer to the next instruction is stored toward the next time that task is invoked. Multiple tasks that need to be coordinated can be linked with subtasks that can be guaranteed complete execution by allocating sufficient instructions to those subtasks.
Abstract:
Fuzzy logic programming is provided for machine and process controllers. New input and output instructions are devised for ladder diagram programming, as well as methods of downloading fuzzy logic instructions from a programming terminal to a programmable controller processor and methods for executing such instructions in the programmable controller processor.
Abstract:
An eight-bit microprocessor sequentially reads controller type instructions from a memory and applies the operation codes of selected ones of the instructions to a hardwired Boolean processor. The microprocessor also couples status words between an I/O image table stored in the memory and the I/O interface racks which connect the programmable controller to the machine being controlled. In general, those controller type instructions which are word oriented are executed by the microprocessor and those which are single-bit oriented are executed by the Boolean processor. The Boolean processor is operable in combination with the microprocessor to examine selected status bits in the I/O image table and to set selected status bits therein to a logic state which is determined in part by the state of the examined status bits.
Abstract:
An industrial control processor is employed in a numerical control system to operate the servo mechanisms on a machine tool in response to a part program stored on a tape. The industrial control processor includes unique hardware and software features which also allow it to operate as a programmable controller to control the discrete digital devices associated with the machine tool. The industrial control processor is programmed with a conventional computer type instruction set to perform numerical control functions and is programmed with a programmable controller type instruction set to perform the machine dependent logic functions. The resulting system maintains the state-of-the-art capabilities of a computer numerical control (CNC) and adds to it the flexibility and programming ease of a programmable controller.
Abstract:
A method of fine tuning the "gain" of a fuzzy logic controller, the controller having input and output membership functions where the input membership functions receive one or more inputs and are grouped in sets according to each input, where the gain is tuned by uniformly scaling the domains of one or more of the sets of the input membership functions.
Abstract:
A programmable controller interfaces a numerical control system to sensing and operating devices that control the auxiliary functions on a machine tool. In the controller a microprocessor is coupled to a random-access memory (RAM) and an electrically alterable read-only memory (EAROM) through an address bus and a data bus. The RAM stores a user control program and an I/O image table that depicts the status of the sensing and operating devices on the machine tool. Under program control the microprocessor verifies the contents of the RAM and copies the verified contents into the EAROM. If the contents of the RAM are altered or lost, the master copy of data stored in the EAROM is reloaded into the RAM.
Abstract:
Fault detection hardware is employed at the I/O interface racks of a programmable controller to detect fault conditions which may occur there. An I/O fault line is connected in daisy chain fashion between the I/O interface racks and the controller processor, and when a fault is indicated at any of the I/O interface racks, it is communicated to the controller processor through this line. The indicated I/O fault freezes, or holds, a microprocessor in the controller processor, and if the I/O fault persists for a preselected time interval, all operating devices connected to the programmable controller interface racks are decontrolled. A watchdog timer is also provided in the controller processor for detecting malfunction conditions which may occur at the processor. When such a condition is detected, the operating devices connected to the programmable controller interface racks are decontrolled.
Abstract:
A simple modification to a proportional integral controller allows for non-linear control strategies while maintaining the simplicity of set up and tuning of the loop through modifying the proportional and/or integral gains K.sub.p, K.sub.j by a linear or parabolic function of the feedback error signal. Provision is made for symmetrical or asymmetrical gain modification functions.