Joseph Brindley

Controllability of buildings: a multi-input multi-output stability assessment method for buildings with slow acting heating systems

Abstract The paper describes a methodology to assess the controllability of a building and its servicing systems, such as heating, lighting and ventilation. The knowledge for these methods has been transferred from design processes and methods used in the design of aircraft flight control systems to establish a modelling and design process for assessing the controllability of buildings. The paper describes a holistic approach to the modelling of the nonlinear and linear dynamics of the integrated building and its systems. This model is used to analyse the controllability of the building using Nonlinear Inverse Dynamics controller design methods used in the aerospace and robotics industry. The results show that this design approach can help the architects in their decisions on which building design and services to use. Furthermore, the results demonstrate how the same method can assist the control systems designer in developing complex control systems especially for buildings designed with a climate adaptive building (CAB) philosophy.

Robust nonlinear HVAC systems control with evolutionary optimisation

Purpose – The purpose of this research is to design a robust high-performance nonlinear multi-input multi-output heating, ventilation and air conditioning (HVAC) system controller for temperature and relative humidity regulation. Buildings are complex systems which are subjected to many unknown disturbances. Further complicating the control problem is the fact that, in practice, buildings and their systems have static nonlinearities such as power saturation that make stability difficult to guarantee. Therefore, in order to overcome these issues, a control system must be designed to be robust (performance insensitive) against uncertainties, static nonlinearities and effectively respond to unknown heat load and moisture disturbances. Design/methodology/approach – A state of the art nonlinear inverse dynamics (NID) technique is combined with a genetic algorithm (GA) optimisation scheme in order to improve robustness against uncertainty in the systems modelling assumptions. The parameter uncertainty problem ...

Non-Linear Autopilot Design Using the Philosophy of Variable Transient Response

The novel non-linear controller design methodology of Variable Transient Response (VTR) is presented in this research. The performance of VTR is compared to that of successful non-linear controller designs (such as Robust Inverse Dynamics Estimation and a traditional autopilot design) by application to a non-linear missile model. The simulated results of this application demonstrate that the inclusion of VTR into the RIDE design results in a 50% improvement in response time and 100% improvement in settling time whilst achieving stable and accurate tracking of a command input. Analysis demonstrates that VTR dynamically alters the system’s damping, resulting in a non-linear response. The system stability is analysed during actuator saturation using non-linear stability criteria. The results of this analysis show that the inclusion of VTR into the RIDE design does not compromise non-linear system stability.

Design and simulation of a non-linear, discontinuous, flight control system using rate actuated inverse dynamics

This article presents the novel non-linear controller design method of rate actuated inverse dynamics. The rate actuated inverse dynamics controller design uses a novel variable structure control based anti-windup method to ensure that the actuator does not become overdriven when rate or deflection limits are reached. This allows the actuator to remain on both rate and deflection limits without the system becoming unstable. This is demonstrated in a non-linear simulation of a missile body rate autopilot using a multivariable controller designed using rate actuated inverse dynamics methods and, for comparison, a controller designed using robust inverse dynamics estimation. The simulation is performed with an advanced solver which uses a discontinuity detection mechanism to ensure that errors do not occur during the simulation due to the presence of multiple discontinuities. The results show that using a smaller actuator, with reduced rate limits, is not possible with the robust inverse dynamics estimation design. Conversely, the rate actuated inverse dynamics design demonstrates excellent performance, despite the actuator limiting in both deflection and rate of deflection. This illustrates the possibility of using smaller, less powerful actuators without sacrificing system stability.

Auto-Tuning for High Performance Autopilot Design Using Robust Inverse Dynamics Estimation

A novel auto-tuning method for the Robust Inverse Dynamics Estimation (RIDE) controller algorithm is presented. The RIDE controller is applied to a high performance aircraft model. The tuner utilises a constrained genetic algorithm to automate the tuning process. The stability constraints on the algorithm ensure system stability whilst allowing for the optimum controller parameters to be selected. The results of the tuner are compared with that of another tuning method which utilises unconstrained optimisation so as to highlight the efficacy of constrained optimisation for this application. It is shown from the results that the constrained genetic algorithm optimisation scheme offers a highly effective tuning solution for the RIDE control algorithm which can be used to attain safe and high performance control.