Feedback system for robot controller

A feedback system for providing a first feedback signal representing incremental motion of a movable means in a first direction along an axis and a second feedback signal representing incremental motion in a second opposite direction along the axis, in response to first and second encoder signals from an encoder means, the encoder signals having first and second states depending upon motion of the movable means sensed by the encoder means, the feedback system comprising:

• first means for receiving the first encoder signal and producing signals which indicate the state of the first encoder signal and whether the first encoder signal has changed state within a predetermined time interval;
• second means for receiving the second encoder signal and producing signals which indicate the state of the second encoder signal and whether the second encoder signal has changed state within a predetermined time interval;
• and
• memory means having inputs for receiving the signals from the first and second means, having outputs for providing the first and second feedback signals, and having stored code defining a predetermined relationship between the signals from the first and second means and the first and second feedback signals, the memory means producing the first and second feedback signals as a function of the signals from the first and second means and the stored code.

A feedback system for providing first and second feedback signals as a function of first and second encoder signals, the feedback system comprising:

• clock means for providing a clock signal;
• first flipflop means having an input for receiving the first encoder signal, a clock input for receiving the clock signal, and an output for providing a first signal having a state which is a function of a state of the first encoder signal when the clock signal is received;
• second flipflop means having an input for receiving the first signal, a clock input for receiving the clock signal, and an output for providing a second signal having a state which is a function of the state of the first signal when the clock signal is received;
• third flipflop means having an input for receiving the second encoder signal, a clock input for receiving the clock signal, and an output for providing a third signal having a state which is a function of a state of the second encoder signal when the clock signal is received;
• fourth flipflop means having an input for receiving the third signal, a clock input for receiving the clock signal, and an output for providing a fourth signal having a state which is a function of the state of the third signal when the clock signal is received;
• and
• memory means having inputs for receiving the first, second, third, and fourth signal, having outputs for providing the first and second feedback signals, and having stored code defining a predetermined relationship between the first, second, third and fourth signals and the first and second feedback signals, the memory means producing the first and second feedback signals as a function of the first, second, third, and fourth signals and the stored code.