Although the application of lower limb exoskeletons has been widely studied, current designs still face challenges such as excessive weight, insufficient compliance, and limited modularity. To address these issues, this paper proposes a modular, flexibly actuated lower limb exoskeleton robot. The degrees of freedom and range of motion are determined based on an analysis of human lower limb biomechanics. A lightweight structure is achieved through the use of adjustable modular mechanisms and materials such as aluminum alloy and carbon fiber. Cable-driven actuation is employed at the knee and ankle joints, where high-strength, wear-resistant tungsten cables replace traditional steel cables, and motors are positioned on the thigh and shank to reduce inertial torque. Compact torque sensors are integrated at the hip, knee, and ankle joints, while magnetic encoders at the knee and ankle joints are used to calibrate cable-driven errors. A multidimensional hybrid sensing system is developed, incorporating torque sensors, IMUs, and encoders. For control, a PD strategy with dynamic feedforward compensation is implemented for joint angle tracking. Experimental results show that, under no-load conditions, the tracking errors are within 1.58° at the hip, 2.31° at the knee, and 1.72° at the ankle.