Unmanned aerial vehicle with collision tolerant propulsion and controller

Vertical take off and landing (VTOL) unmanned aerial vehicle (UAV) comprising a multi-propeller propulsion system, an outer protective cage surrounding the multi-propeller propulsion system, an autonomous power source, a sensing system, and a control system connected to the sensing system to receive measurement signals from the sensing system, the control system electrically connected to the multi-propeller propulsion system to control motors of the propulsion system, the sensing system comprising at least an orientation sensor and a displacement sensor configured to measure the orientation and displacement of the multi-propeller propulsion system, the multi-propeller propulsion system comprising at least two propellers arranged spaced apart in a non-coaxial manner, each propeller comprising a motor having a stator and a rotor coupled to propeller blades, the control system comprising at least one microprocessor and at least one non-volatile memory in which at least one control program is executable by the microprocessor to control the multi-propeller propulsion system for flight or hovering of the VTOL UAV, wherein the control system comprises a program for stabilizing orientation of said VTOL UAV configured to reverse thrust on at least one propeller distal from a point of contact (P) with an obstacle, delivering therefore a downwards force to said VTOL UAV via said at least one propeller, while controlling a motor of a proximal propeller from the contact point (P) to generate lift, delivering therefore an upwards force to said VTOL UAV via said proximal propeller, the thrust of the distal and proximal propellers being controlled to exert lift on the VTOL UAV to counteract gravitational force (G) thereon and apply a moment of rotation (M) about said point of contact (P) to stabilize the position of the VTOL UAV or to counteract torque resulting from inertia.