This paper describes an improved force control scheme for the operation of a pneumatic-muscle driven parallel platform. The platform is composed of 6 RRPS legs, each leg being equipped with a coaxial coil spring and a fluidic muscle providing push and pull forces. The platform is thus virtually free of stick-slip effects. In previous works, the basic design steps as well a basic control algorithm were presented. In this regard, the basic design — including singularity and collision avoidance as well as achievement of target forces in the complete workspace — could be verified using interval analysis. In this work, the control scheme has been extended, allowing for a more stable set-point achievement as well as small overshooting. This makes the platform now suitable for realizing force control protocols of forces of up to 400 N with an error of approximately 0.3 N in steady-state mode.