Abstract: An optimal estimation method is developed to dynamically determine track tension for a new type of deformable tracked wheelchair robot.Compared with traditional tracked mobile mechanism which keeps track tension constant,it can reduce power consumption obviously to determine tension dynamically.Considering the complexity in track tension modeling, a fuzzy logic decision making method is developed,which uses main influential factors on the track tension as its inputs. Then combining with least square method,an optimal estimation algorithm of track tension is obtained.Because of the low speed feature of the process when the wheelchair negotiates obstacle,a statics model of the wheelchair for the initial stage of climbing stairs is developed according to the result of the optimal track tension estimation algorithm.Simulation result proves that the wheelchair can climb stairs stably when it takes advantage of tension estimation algorithm.At the same time, it also shows that the power consumption is reduced greatly by dynamically determining the track tension.