Smartphone shell temperature controller automatic tuning method

The performance of mobile Systems-on-Chip is frequently limited by elevated shell temperatures that degrade user comfort. This paper presents a PID-based thermal controller that co-manages central and graphics processing units’ frequencies, featuring a novel auto-tuning framework to optimize its parameters for any given device. The principal result is a universal tuning formula, derived by simulating diverse hardware thermal models to establish a polynomial relationship. This formula maps easily measurable system characteristics from an on-device relay experiment to optimal PID parameters, ensuring controller stability across different hardware configurations, with average gain margin of 2.14, and phase margin of 78°. Validation on a commercial smartphone confirmed the formula's accuracy, yielding PID parameters with less than 5% deviation from the theoretical optimum. When benchmarked against the device's default hysteresis governor, our controller demonstrated significant gains, simultaneously increasing sustained performance by up to 9% while reducing thermal limit violations by up to 2.6 times. This work provides a validated, practical framework for automatic tuning of control systems, that maximize mobile device performance within user comfort constraints.