System and method to shift transmission in machines

A machine, comprising:

• a power source to generate power;
• a transmission operably coupled to the power source to receive power from the power source and transfer the power to one or more traction devices of the machine to facilitate machine motion;
• a brake unit to apply braking force against the one or more traction devices to retard machine motion;
• a control system for shifting the transmission, the control system including:
• a controller configured to:
• detect a request for a directional shift of the transmission;
• determine a ground speed of the machine in response to the request;
• override the request if the ground speed is above a ground speed threshold;
• prepare the machine for the directional shift by:
• limiting an output speed of the power source;
• and
• issuing a command to the brake unit to reduce the ground speed of the machine;
• and
• validate and raise the request to the transmission to execute the directional shift if the ground speed is below the ground speed threshold,
• wherein the power source includes an internal combustion engine, and for limiting the output speed of the power source the controller is configured to:
• detect the output speed of the internal combustion engine;
• compare the output speed of the internal combustion engine to an engine speed threshold;
• and
• reduce a supply of fuel into the internal combustion engine if the output speed of the internal combustion engine is above the engine speed threshold.

A control system for shifting a transmission in a machine, the control system comprising:

• a controller configured to:
• detect a request for a directional shift of the transmission;
• determine a ground speed of the machine in response to the request;
• override the request if the ground speed is above a ground speed threshold;
• prepare the machine for the directional shift by:
• limiting an output speed of a power source of the machine;
• and
• issuing a command to a brake unit of the machine to reduce the ground speed of the machine;
• and
• validate and raise the request to the transmission to execute the directional shift if the ground speed is below the ground speed threshold,
• wherein to issue the command, the controller is configured to:
• determine a speed error signal by comparing and deducing a difference between an actual ground speed of the machine and a target ground speed of the machine;
• scale the speed error signal to respectively arrive at a proportionally scaled error signal and an integrally scaled error signal;
• and
• summate the proportionally scaled error signal with the integrally scaled error signal to arrive at the command.