Technical systems with effectors are deployed still more and more not only in industry but also in areas such as military, healthcare, aerospace and others. Effectors can manipulate even with fragile, elastic or dangerous objects where it is essential to secure the maximum security of the operation. Failure could result not only in damage to the handled object and its surroundings but also in health injuries or even death of human workers.

For save grip and subsequent transport, the correct gripping force must be obtained. This can be estimated based on information about the handling object (strength, weight, the centre of gravity, possible gripping surfaces, etc.). However, these parameters are not always known. In this case, the gripping force can be determined for example by sensors and various methods [Lim 2014, Chuah 2014], by operator experience, or by the trial-and-error method. It is not possible to set the grip force on the effector correctly without measuring it. The more precisely the force amplitude should be set, the more precisely it has to be measured. This article focuses on measurement of the grip force of an existing effector and the problems associated with modifications of the effector. Due to the design of the effector, it was not possible to provide the gripping force with the required precision. For this reason, the effector was modified by adding a set of sensors from which it is possible to obtain more accurate information about the actual gripping force. The installation of